Warning!! Check your old galleries, I have over 20 galleries that the watermark "PROOF" has been applied to whole galleries.
These galleries were set to "Default" in gallery settings. I had to go into settings and reset to a specific watermark.
BTW, I've been through this in the past a couple times finding PROOF applied and fixed them all. Some of these same galleries.
EDIT: notice one gallery so far that has watermark off/disabled but PROOF shows on a photo.