Hello,
Seems the discussion board is also affected with this issue - I received an error when posting my original report... 
We recently had an XML issue in the software I'm working on and I discussed it with a coworker on Spark. The issue was caused with the presence of this sequence of characters: ] ] > (note that I added spaces between the characters to be able to post). These characters are used to end a CDATA block, but XML really doesn't like to see it without the start of the block.
Since I had typed these characters in the chat, they are found in the contact history. The display stops with the previous entry, with no indication that something went wrong.
I guess the '>' character should also be encoded in the logs, just like " and < are...
