[Dolgubon]

If there is a very long bit of text in a reply without spaces, then the reply, edit, quote, and multiquote buttons get hidden on mobile, along with the end of the text of the post.
There is some other condition to trigger it, but I'm not quite sure what. (Maybe using the advaned editor?) You can see another example of the issue here: https://www.esoui.com/forums/showthread.php?p=49182#post49182