This question already has an answer here:
Say a user is called Beowulf. In a comment under his posting you try to start with "@Beowulf". I know I've seen this done. But several times, the software has edited that out when I hit "save". I have no idea how to tell when this will happen and when it won't. That the software can overrule my decisions about content seems bizarre, not to mention abusive. What's going on?