I have ST8 MP5, I heda all the ref planes but the ref plane names stay on screen, is this only here or also on your screen?
Is it just this one file? In what version was this file made?
I'm still on MP4 and haven't installed MP5 yet. That said, I haven't seen this issue.
It looks to be only that file.
For me, the names are only visible when the name fits inside the plane. This is relative to your zoom level. Make the name shorter and or make the planes larger.