… the edits I made don't stick …

What were your edits?

Please be specific.

The only edits I can suggest, are layout adjustments where the (horizontal) distance between barlines is edited by dragging barlines.

Such edits will be reverted if the option

Document menu > Document Options > Multimeasure Rests > Update Automatically

is selected.

De-select “Update Automatically”, and the barlines will stay where you drag them.

Right, sorry. Mainly note/pitch changes.

I have not encountered this, sorry.

But I am using Mac Finale, and you are using Windows Finale.

Perhaps this is an issue with Windows Finale (?)

This is not a complaint I have seen. Are you still on Win 10 per your signature or are you now on Windows 11. We’ve read that support for 26 over Win 11 is limited..If that’s the case, time to download the 27 demo to see if you have the same problem.

Yes, I'm still on Windows 10.

There is a bug that was introduced in v26 (on Windows at least) related to guides. When you delete a guide, that deletion is not recorded in the undo/redo list as in previous versions. When you make certain edits after deleting a guide, the guide comes back and will continue to come back after being deleted. I'm wondering if this bug is somehow related to other edits (like in my case with note/pitch changes)? Perhaps there is some kind of memory leak issue.