Rotobrush erasing my footage whenever i try to use it

So i stmbled upon this issue today and i have no clue how to fix it. Whenever i try to use rotobrush the add icon appears for few seconds and thenit dissapears and it tuns into regular round brush. I tried checking if i have any other buttons active or anything also updated and tried to clear the cashe and the problem still persitst. I tried checking it on files i managed to use roto before and the problem is always the same.
Do you know what could be the issue or what i missed?