User blog comment:Rappy 4187/Technical Update: January 27, 2016/@comment-24014422-20160131174959/@comment-957747-20160131202544

It's possible they are using a script like UserTags or ProfileTags to change their tags and not re-adding them through this script. If this is not the case, please send a Special:Contact with details (page links help) so that it can be investigated.