I can't seem to find any information or similar reports on the net, it's an issue that's quite hard to search for. I'm not even sure how to put what is happening into keywords that google would get right.
This happens consistently after a few hours of use. It only happens in the shell, while all applications (including gtk+ themed menu bars) seem to render fonts perfectly fine.
And once this happens, I have to open gnome tweak tool and go to the font hinting settings and just change it to any other value, which I assume re-renders the fonts.
Any idea on how I can fix this for good?