Autocomplete when typing usernames or community names not working

On my desktop right now (I can't remember if this happens on mobile as well): I was typing a username and community name in a post I was creating, and I got a pop-up showing the name I was trying to write out. I was not finished typing the name, so I clicked it thinking it would complete the entry (and make the appropriate link), but instead left the name as it was (incomplete) and moved the cursor back to the beginning of the paragraph I was writing in. I'm assuming its not supposed to do that?