I've had three games since October where midway through the game, I am moving troops across the Pacific (once from South America toward Australia, once from US to Japan and once from Japan to US, where most of my troops will move across near where the International date line would be, but one or more transports (first two times it was aircraft, last time naval), will get stuck and I can only move them up, down, or backward. It is a north/south barrier somewhere just west of Hawaii and mainland Alaska. I was able to move the transport all the way up to the Arctic Ice Shelf and back down, but not advance toward the US. I tried exiting and reloading too. Finally, I landed on one of the Aleutian Islands and then turned East toward Alaska and it worked. (Something about touching land helped reset the bug). The other two times I never found a way to advance.
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War does not determine who is right - only who is left.
Bertrand Russell