This has been bugging me for ages, but now it's only gotten worse.
I experienced this issue:
I can't seem to fix it, no matter what I do. if I disable all add ons EXCEPT SUF, it STILL appears there in that spot underneath the unit frames. It also does it with the raid pop out, it never used to do this, it was sudden a while back and tolerable at first, but now it's just gotten worse.