That blue box showing post number where you are (like 9/10), when you get to last post, it's directly on top of the "reply" - button. And masks them...
At least on Firefox it is. Am I missing something obvious?
It kinda makes me not want to try posting, from mobile.
Not that it would be the first time, though... On some other (can't remember what the software was) forum software (Xenforo?) there was a problem with side menu. Which on FF mobile, didn't scroll, unless you zoomed the view first...