On my new Librem 14, with Arch Linux (endeavourOS) and KDE Plasma installed, there is an attached display shown, even though there is no one attached.
This also causes a problem when logging in after the laptop has freshly booted up. Then both displays are shown overlapped on the Laptop screen.
To eleborate what I mean with the overlapping screens during the login, here is a photo of this behaviour:
Do you charge via the USB type C port?
No, nothing connected via USB C.
Okay. I am not an expert. This was just a suspect.
As a workaround I could imagine to make a script to configure the screens to a correct setting and put that script somewhere so that it gets executed at startup or login or so. arandr is your friend in generating such a script, if you don’t want to do it manually.
Otherwise you have to wait if some expert makes a statement. I am not really Linus Torvalds you know. I am just his forgotten twin. ^^ 
sounds like an issue specific to Endeavor or whatever tweaks they’ve made. No such issue here on Manjaro w/kernel 5.11.22-2
As this does happen with my Librem 14 on PureOS as well and connecting a display via HDMI doesn’t work too, the purism support currently thinks this is a hardware issue.
