Hidden rests in V2 etc. are drawn over the top of notes in V1
1) Add a few notes in V1 around the middle of the staff
2) Now add a few notes and rests in V2 in the same measure
3) Note that the V2 rests are positioned to avoid clashing with the V1 notes
4) Select the V2 rests and hide them
5) Note that they're now drawn over the top of the V1 notes
I understand as they're invisible there's technically no need for the automatic collision avoidance logic to kick in, but it does make the score look quite messy while you're working on it, and harder to interact with individual elements. At the least I'd expect them to be drawn "under" the V1 notes.