The edit by user168946 was clearly a vandalism: mathoverflow.net/posts/26284/revisions (And so was this suggested edit.)

The user now has a deleted account - whoever deleted it probably missed that they edited this post. After the next SEDE update, it might be worth checking whether some actions by this user still remain on site: data.stackexchange.com/mathoverflow/query/1333512/…

Although I think that any problems would have been noticed - as in this case.

(When I rejected the edit suggestion linked above, I somehow missed the previous edit - I have noticed it only after finishing the review.)