Trumpet Single-Note Dynamics Glitch

I have a section in a large score that seems to be a bit buggy dynamic-wise. Essentially, the trumpet is supposed to decrescendo from mf to ppp during a sustain, then re-enter at mf after several beats of rest. However, the trumpet seems to be stuck at the ppp level from there on after. Playing around with it, the issue is not isolated to the staff - copying the part into any other track yields the same result. It is also not isolated to the patch in the mixer - for the record, the patch is Trumpet Expr. from MuseScore General HQ,

If I change the dynamics around, I get roughly the same outcome so long as there are two dynamics and a hairpin - for example, if it is a crescendo from mf to f with a re-entrance at ppp, the subsequent notes seem to almost swell into a forte. I've checked in the synthesizer to make sure that I'm not just hearing things, and the volume gauge confirmed what I'm hearing. I've also tried copying the section into a new score, but the issue does not happen there.

As I mentioned before, the score is rather large, in addition to being transcribed from a copyrighted work, so I'm not attaching it initially. If having the score would help, I'd be happy to upload.