Weekly Mission Crash

Maragost

For some unknow reason the game freezes while i'm playing the weekly which gives 40 tokens. I played all the others weekly missions before without problems and even the campaign missions are fine. I didn't install anything new since the last update of Heroes so i don't think it may be a problem of RAM. Anyone having the same issue?
I start the mission and soon or later it freezes.
Never at the same point but i never reach the end of the mission.