In my previous comment I posted the AI on crazy out of no where would just started throwing down armies of 100+ as I surrounded them. The PC version of Risk had this same problem as the AI neared defeat it would start throwing out armies of 255 repeatedly even though it didn't have the cards or territory to support this. Hasbro the maker of PC Risk released a patch to fix this bug.
Not sure if I'm the first to encounter this on crazy. I had all of North America except for 2 spots, all of South America, Africa, Antarctic, and Australia with singles in europe and asia with armies of 58 and 72. Behind the fog were the 6 AI's so no one could be pullling huge armies and I was laying down 40 a turn. Just as I start my push in europe Armies of over 100 start appearing at all my points of contact. At first I thought all the cards were coming out but they didnt stop I stopped the first couple but waves of 50 and 60 armies kept coming and there is no way with me having most of the map the AI's controlled enough territory to keep throwing those out. About 10 turns later I was pushed all the way back to antarctica with massive armies still coming. Figure has to be a bug wasn't enough territory behind fog for the all the AI's to just start throwing down massive armies and it was all the AI's wasn't just one or two.
Best way to know what happened after you lost is to surrender, then use history to look behind the fog. There aren't any secrets - you can see how they got every single army
 "WarLight"){kind=icon}
WarLight doesn't do this. The AIs play by the exact same rules as you do.