@ct_bergstrom When this has happened to me, it's because some other reviewer asked for a sizable change and they want all reviewers to approve the change.
The big problem I've started having is getting to the point where I have a problem, the author disagrees and refuses to make changes, and the editor keeps sending our correspondence back and forth to the point where there's no progress in discussion. It's gotten to the point where I have to tell the editor "I don't want to see this again, you have to make a decision."