You guessed it, it's another Rules update. Check here for more info

Tag changes for image #35137

Image		Tag	Action	Timestamp	User	Retained?
35137		+-SH pegasus Unwatch Watch Unspoiler Spoiler Unhide Hide Sign in to Watch Filter 5921	Added	4 days ago	Alicorndogz Stop! This user is a staff member. Ask them before reverting their changes.	Yes