MyBB Hacks

Hi guys nice site you have here pleased I found it

I have a problem with mybb and cant find how to fix it anywhere.
here is what happens when someone makes a post in any section or reply to a post some of the text is missing.

when I click full or quick edit I can se the full text. I have no Idea what's wrong with it I have changed theme and it still does it have any of you guys any idea what could be wrong please

Thank you inadvance

What kind of the missing?
It is replaced by other text or what?
Maybe you need to check whether you have a plugin or core file edit that cut the post message.