I’m not sure what you mean by “Chances are it got fixed itself” but the error is still there.
$ sudo apt-get update
Get:1 https://repo.puri.sm/pureos amber InRelease [5,784 B]
Get:2 https://repo.puri.sm/pureos amber/main Translation-en [5,753 kB]
Get:2 https://repo.puri.sm/pureos amber/main Translation-en [5,753 kB]
Hit:5 https://repo.puri.sm/pureos amber/main amd64 Packages
Ign:5 https://repo.puri.sm/pureos amber/main amd64 Packages
Hit:2 https://repo.puri.sm/pureos amber/main Translation-en
Hit:6 https://repo.puri.sm/pureos amber/main amd64 DEP-11 Metadata
Ign:2 https://repo.puri.sm/pureos amber/main Translation-en
Ign:6 https://repo.puri.sm/pureos amber/main amd64 DEP-11 Metadata
Err:5 https://repo.puri.sm/pureos amber/main amd64 Packages
lzma_read: Read error (7)
Get:2 https://repo.puri.sm/pureos amber/main Translation-en [28.8 MB]
Ign:2 https://repo.puri.sm/pureos amber/main Translation-en
Reading package lists... Done
E: Failed to fetch https://repo.puri.sm/pureos/dists/amber/main/binary-amd64/Packages lzma_read: Read error (7)
E: Some index files failed to download. They have been ignored, or old ones used instead.
Since I don’t hear anyone else saying they have this lzma_read: Read error problem then I suspect it’s a problem I brought upon myself. I’m reinstalling the operating system. Thanks for your help!