When I a @-mention another user in a comment on my mobile phone, using the full responsive version, the suggested username is on the top left of the comment field. At this location it is very close to the username of the person that wrote the last comment. This leads to clicking that persons name, and thus visiting their profile, every now and then. This is especially annoying when you just wrote a very long comment, and put the @-mention at the end of the comment. Now you could reason that it is better to start with the @-mention, but sometimes it is just more natural to the flow of the language to put it at the end.
Can the location of the suggested username be improved, as to avoid incidental clicks on a hyperlink?
Perhaps a better place would be below the comment. If it then collides with the post button it really isn't too big of a problem, because your comment is saved and can be edited easily.