the problem is because i mounted discourse from host to docker, so folder /var/discourse in shared directory between host (which is on windows) and client os (which is on linux). And because of that, there are some problems.
One of the problem i described today: Problem with development on Windows with Docker and mounted volume
when discourse try to generate some files in “tmp” directory it gets errors, because it expect filesystem to be case sensitive, but mounted directory uses windows ntfs filesystem, that is case insensitive.
If i can somehow change location of tmp dir, so it will be in /tmp, then problem will go away, because guest os filesystem is ext4 which support case sensitive directories