Selectors jumping and duplicating in USS files

I usually have couple of .uss files inside of one .uxml file, but during my development - clicking around, modifying stuff and saving ui builder i get bugs all the time. Specific selector is duplicating itself. Sometimes in the same uss file, sometimes in other uss. Sometimes it just moves on its own to different uss. Bug?

I am using Unity 2023.2.20, but i think i always had this problem (dont remeber all the versions. been using ui toolkit for more than a year).

Thank you

Those are definitely bugs, it always helps to open a ticket: Help > Report a Bug…