Bug report: Can't save after view modification

If I save a score (or load an existing score), then change the view (e.g., from page to galley) then I can’t save that file without first altering something in the score.

That’s because changing the view type is not an undoable operation, and as such doesn’t dirty the score. Although you can’t save the score in this state, the good news is you wouldn’t lose anything if the program crashes or if you close the project, because you don’t have any unsaved changes except for a change of view, which is obviously easy enough to do once you reopen the project again.