In the example I've attached the 2nd, 3rd and 4th system 1st bar bassoon part should show quavers 1 and 3 beamed with an internal rest. However, the beam on the 4th system has disappeared. If I move the "stacc" or the "f" on the 4th system bassoon part, then the beam reappears, but another beam in system 2 or 3 disappears. And so one. I can go round and round making minor adjustments but I can't find a way to make all the unstable beams appear together - except - then the score is first loaded. All seems well until I start editing.
Just in case you don't see the problem when you load the fragment score i've attached, the select the "stacc." at the botton left, and move it down a minimal amount. Now look at systems 2 and 3. You should see:
What is causing this, and how do I avoid it.