This sounds similar to what I described here. Seems to mostly happen while connecting the L5 to an external dock. Must be software related as I have the exact same behaviour on both of my L5’s.
I managed to catch the attached journalctl log this morning, but I couldn’t do dmesg as every sudo command in the terminal is blocked.
jan 23 08:56:26 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:56:26 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:56:26 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:56:26 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:08 pureos phoc[806]: [libinput] event9 - SIPODEV USB Composite Device: client bug: event processing lagging behind by 14ms, your system is too slow
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 08:57:44 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 08:58:16 pureos phoc[806]: [libinput] event9 - SIPODEV USB Composite Device: client bug: event processing lagging behind by 14ms, your system is too slow
jan 23 08:58:31 pureos org.gnome.Geary[2283]: *[wrn] 08:58:31.0816 Geary.Imap: [account_02] [imap] [closed:INBOX selected RW] GearyImapClientSession: Keepalive error: ---- noop: Disconnected
jan 23 08:58:43 pureos phoc[806]: [libinput] event9 - SIPODEV USB Composite Device: client bug: event processing lagging behind by 15ms, your system is too slow
jan 23 08:59:34 pureos phoc[806]: [libinput] event9 - SIPODEV USB Composite Device: client bug: event processing lagging behind by 15ms, your system is too slow
jan 23 08:59:34 pureos phoc[806]: [libinput] event9 - SIPODEV USB Composite Device: WARNING: log rate limit exceeded (5 msgs per 60min). Discarding future messages.
jan 23 09:00:00 pureos kernel: usb 3-1: USB disconnect, device number 2
jan 23 09:00:01 pureos kernel: usb 3-1.1: USB disconnect, device number 3
jan 23 09:00:01 pureos kernel: [drm] hpd irq
jan 23 09:00:01 pureos kernel: xhci-hcd xhci-hcd.5.auto: remove, state 4
jan 23 09:00:01 pureos kernel: usb usb4: USB disconnect, device number 1
jan 23 09:00:01 pureos kernel: tps6598x 0-003f: The interrupt is masked , how did it fire ?? 380100a
jan 23 09:00:01 pureos kernel: bq25890-charger 3-006a: Upstream supply changed: 0.
jan 23 09:00:01 pureos kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
jan 23 09:00:01 pureos kernel: xhci-hcd xhci-hcd.5.auto: USB bus 4 deregistered
jan 23 09:00:01 pureos kernel: xhci-hcd xhci-hcd.5.auto: remove, state 1
jan 23 09:00:01 pureos kernel: usb usb3: USB disconnect, device number 1
jan 23 09:00:01 pureos kernel: bq25890-charger 3-006a: Upstream supply changed: 0.
jan 23 09:00:01 pureos kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
jan 23 09:00:01 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 09:00:01 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 09:00:01 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 09:00:01 pureos phoc[806]: [types/output/cursor.c:223] Failed to get cursor display formats
jan 23 09:00:01 pureos phoc[806]: [types/output/cursor.c:269] Failed to pick cursor format
jan 23 09:00:01 pureos phoc[806]: [types/output/cursor.c:354] Failed to render cursor buffer
jan 23 09:00:01 pureos kernel: [drm] Connector status: 0
jan 23 09:00:01 pureos kernel: [drm] HDMI/DP Cable Plug Out
jan 23 09:00:01 pureos phoc[806]: invalid unclassed pointer in cast to 'PhocOutput'
jan 23 09:00:01 pureos kernel: [drm] Connector status: 0
jan 23 09:00:01 pureos kernel: usb 3-1.2: USB disconnect, device number 4
jan 23 09:00:01 pureos gsd-xsettings[1251]: Failed to get current UI legacy scaling factor
jan 23 09:00:01 pureos gsd-xsettings[1251]: Failed to get current UI legacy scaling factor
jan 23 09:00:01 pureos sm.puri.OSK0.desktop[1391]: Debug: Tried file "/home/purism/.local/share/squeekboard/keyboards/terminal/se.yaml", but it's missing: Filen eller katalogen finns inte (os error 2)
jan 23 09:00:01 pureos sm.puri.OSK0.desktop[1391]: Warning: Failed to load layout from Resource: terminal/se: Missing resource, skipping
jan 23 09:00:01 pureos sm.puri.OSK0.desktop[1391]: Debug: Tried file "/home/purism/.local/share/squeekboard/keyboards/terminal/us.yaml", but it's missing: Filen eller katalogen finns inte (os error 2)
jan 23 09:00:01 pureos phoc[806]: [libseat] [libseat/backend/logind.c:148] Could not close device: Device not taken
jan 23 09:00:01 pureos phoc[806]: [backend/session/session.c:357] Failed to close device 109: Resursen tillf?lligt otillg?nglig
jan 23 09:00:01 pureos sm.puri.OSK0.desktop[1391]: Info: Loaded layout Resource: terminal/us
jan 23 09:00:01 pureos kernel: xhci-hcd xhci-hcd.5.auto: USB bus 3 deregistered
jan 23 09:00:01 pureos kernel: bq25890-charger 3-006a: Upstream supply changed: 0.
jan 23 09:00:01 pureos kernel: bq25890-charger 3-006a: Disabling OTG_EN pin
jan 23 09:00:01 pureos gsd-color[1215]: unable to get EDID for xrandr-DSI-1: unable to get EDID for output
jan 23 09:00:01 pureos phoc[806]: [libseat] [libseat/backend/logind.c:148] Could not close device: Device not taken
jan 23 09:00:01 pureos phoc[806]: [backend/session/session.c:357] Failed to close device 114: Lyckat
jan 23 09:00:02 pureos pulseaudio[854]: ALSA väckte oss för att skriva ny data till enheten, men det fanns inget att skriva.
jan 23 09:00:02 pureos pulseaudio[854]: Förmodligen är detta ett fel i ALSA-drivrutinen ”snd_soc_simple_card”. Vänligen rapportera detta problem till ALSA-utvecklarna.
jan 23 09:00:02 pureos pulseaudio[854]: We were woken up with POLLOUT set -- however a subsequent snd_pcm_avail() returned 0 or another value < min_avail.
jan 23 09:00:29 pureos systemd[818]: Started Run MMSmonitor.
I will try to catch more next time it happens.
Edit: sudo being blocked means no response from any sudo command and have to force kill the terminal.