This actually made me think of something I noticed when trading stuff to my mule. I had 2 browsers open side by side, trading stuff from the right account to the left. when you click on all your items on the right account then click accept, then click accept on the left screen without actually selecting the open browser window first, you will activate the trade timer without actually confirming a trade.
Obviously that could mean nothing at all but I just thought it was strange that you could activate the trade timer on your own screen but the trade not actually go through. I don't know if the way I explained this makes it hard to understand but whatever, figure it out, I'm tired lol.