Board Thread:General Discussion/@comment-46119613-20200811174345/@comment-168424-20200811182646

You have to paste the URL to the user... the new comments system in UCP doesn't really know about wiki user name links... However, it could support @ to auto complete Discussions user links, but I haven't tried it in UCP comments yet.

The number of differences in UCP are vast... some will get more like legacy over time, some never will. Only FANDOM staff can say.