This is a pretty weird bug as I am not sure why these two things would be related but I did confirm it happened to more than one of us on our site.
If you enable the “Only allow specific users to send me personal messages” user preference then when viewing likes on post the users all appear as deleted users with no avatar. The users are not ones added to the messaging preference and are not deleted.
If i disable that setting then “… liked this” shows correctly
