It is difficult to diagnose something “blindly” without a Finale document to examine.

Also, it would be nice to know the the steps you've already taken, so that we can rule out things.

My first guess would be some sort of file corruption.

Something to try (you may have tried this already):

Select that staff/measure as a Stack Selection. Then Copy.

Usually Finale does not “re-calculate” a Stack Selection.

At first it seems impossible to make a Stack Selection of a single staff in a multi-staff document.

The secret: create a Staff Set of only that staff.

Then, while viewing the Staff Set, make a Stack Selection.

I did some more testing. It appears the ensemble template is corrupted as I cannot create a new piece from that ensemble (instant crash). Now I have to track down how to delete an ensemble. I'll make another post as that thread might be more useful to others searching in the future.

Thanks, Peter. Your response prompted me to examine this more closely. I appreciate that!

Actually, no new post. I found the delete button in the ensemble setup dialogue. DUH!  lol But gain, Peter, it was you response to an earlier post that educated me on the inner workings of this truly fine program. Thank you!

https://makemusic.zendesk.com/hc/en-us/community/posts/115000320787-Ensemble-Templates-Location

Quick update. I found the problem...

I had set the main time sig to 3/4 and the composite display as 6/8 3/4. But... when i set the initial time sig to 6/8 with 6/8 3/4 in the display, all is working fine. The template was apparently damaged, but I sort of understand what is happening. Finale is "confused" about how to handle the inset stack when it thinks it's in 3/4 and the inserted measure is displayed as 6/8. I don't know why that is happening, but I'll try to setup a file for you to look at. It's a pretty reliable error. I won't call it a bug, per se, but something that might be fixable via some additional coding.

I assume MM is watching...

Here it is. Initial time sig is 3/4. Display is 6/8 + 3/4. Insert measures, Finale goes nuts with calculations.

Change the initial time sig to 6/8 and no problem. It's probably safe to assume that the opposite is also true. If the initial time sig is 3/4 with 3/4 + 6/8 as the display sig, inserting a stack(s) would creat a similar dysfunction in Finale.

http://www.midilifecrisis.com/misc_images/TestMe.musx

Would love to get your take on that, Peter. Thanks again for all your help over these many years.

Just checked my linked file and, as long as there is a composite display, adding a stack seems to be a problem. Maybe it's because the number of beats in the time sig doesn't match the number of beats in the display? I'm flummoxed. I'll score the work and change the displayed time sig just before I go to print.