Cannot edit all barlines at once, and barlines missing from one staff

SOLVED

Hello, I am arranging some of Grainger's Lincolnshire Posy for brass and everything was going fine while I was formatting and writing the percussion parts, but when I tried to insert a single-line snare staff the barlines dissappeared from the staff. All the other barlines on all other staffs were present, all of which were 5-line staffs and only when I put the snare part on the top of the percussion parts did the barlines disappear. I am able to have the barlines come back when I put the snare staff under the bass drum for example, but when I try to drag the barlines down to connect with eachother it only edits one individual barline instead of all of them like usual.

In short, my problem is the barlines of a staff dissappear and when they come back, it is only possible to edit them individually, not as a whole.
Thanks for your help!

Edit: I forgot to add that it only occurs on this individual score -everything functions fine on all my other scores, so maybe there's an option I'm missing? There are two invisible staffs "above" the area of problem so that may be the issue as well?