Weird characters printed on first line in Vim 8

[ziima]

When I open vim with python file, characters ^[[>1;4590;0c are printed on first line. This happens about half the time.

This started after I upgraded Vim from 7.4 to 8.0. I tried to disable isort plugin, then it stops.

[fisadev]

Quite strange, I tried lots of things and wasn't able to reproduce it. As the issue in syntastic suggests, it might be a problem with vim refreshing which is triggered by vim-isort or syntastic, but not solvable from within the plugins. I still have some things to try, I'll update once I finish doing that.

[ziima]

Additional details: It's actually on the position of the cursor at time vim is opened, which is usually but not always the first char on first line. It looks line a refresh related bug, because the characters disappear if I do some operations, like changing buffer, splitting, etc,