So I added a character tag to a post at e621,
but then i checked the tag history and noticed the character's owner (person-A) had previously removed that character tag (fursona-A).
(Fursonas of person-A and person-B are both in the image. Names of both owners are printed along with copyright-symbol.)

I assume person-A removed it is because (it seems that) person-A and person-B are no longer together.

Is the correct course of action to re-remove person-A's fursona tag?

Otherwise person-A might get annoyed and submit a takedown request.

EDiT: The first artwork i noticed was nude spanking artwork (rated Explicit).
I poked around and found a 2nd piece (at e621) where person-A had removed their fursona-tag (artwork of them clothed and dancing; rated Safe)
Also found a third piece with both furson tags and no one attempted remove fursona-A tag. (artwork also of them clothed and dancing; rated Safe)