Campaign - Waiting for Host

Dear all,

I'm experimenting with some campaign map linking right now. I'm able to load a hero from one map to the next but a bug that occurs randomly plagues me. When i test the map transitions, once in awhile i get "Waiting for Host -> Disconnect"

I've looked everywhere but i cant find any information on what causes this.
I've tried playing around with the triggers and stuff but I can't reproduce the bug.
I'm seriously stumped here..

The question: How do i fix this bug?

+Rep to whomever can help on this one.. I've attached the campaign.

Just type -next to switch between maps. Try it a few times.. The bug doesn't always happen.

Thanks in Advance.

EDIT: It seems to occur if i hit the 'Press any key continue' button without waiting.. Could it have something to do with the cache not being ready if i hit the key too fast?..