When I do the following...
post a comment
start editing the comment I recently posted
see that newer comments have been posted
click the link to show the newer comments
...my editing of my [less than 5 minutes] old comment is cancelled, and I lose the changes I haven't posted.
Comments are limited in both length and importance, so this is not as bad as other possible bugs that could cause loss of unsaved work, but it is annoying and reduces productivity.
Furthermore, it seems unlikely that this behavior is by design, since I can show new comments when writing a new comment of my own and I don't lose my progress composing the new comment.