I'm trying to set up my Linux console - the bare TTY terminal without X. I tried to capture this problem with asciinema but interestingly, it didn't show up there, So I captured it with my own camera, here is a link to the video.
It doesn't appear in [n]vim only, It is completely random and it appears sometimes on the command line as well. I'm pretty sure it has nothing to do with the font. Has anyone ever encountered such a strange behavior before?
Edit:
more info: I'm using ArchLinux and I think there was a problem with the way I installed the OS. In the past, I made a terrible mistake which deleted almost all files in /usr/. Afterwards, I decided I don't need to reinstall the filesystem For example and I only need to reinstall the gnu-core programs and the kernel with pacstrap. This problem appeared after that.
I tried reset and it doesn't help. I tried LC_ALL=en_US.UTF-8 nvim test.txt and LC_ALL=C nvim test.txt in order to see if it's related to Locale settinga as well and it doesn't help either.