Systems colliding/merging

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I have these merging systems. They occur without rhyme or reason that I can tell.

Very odd. All manual staff spacing in Engrave mode is removed?

Yes. And when I try to manually adjust, another becomes “entangled”.

Can you show a screen shot of the same region of music, but in galley view? It looks to me like the problem is that the drum staff has no notes on that system, only a slash region, and that can cause some problems with the way the staff is handled in vertical justification. We have recently fixed a problem in this area and that fix will be included in the next minor update.