Aww. There should be something like a Operator or other user which has the rights to change it?
Maybe JOSM picks the previous comment when pressing ENTER and when you’re still in the Comment field. At least that is my experience. It was not 1 time, but 3 times.
And I could recover the right comments just by looking back in JOSMs Commit screen, so the comment were changed and saved on disk?
Next changes I will look if the comment is really there when pressing Uploading…