I was playing as France and happened to glance in the eastern hemisphere, only to notice something very interesting: an absolutely gigantic line of units parading through the Philippines. Upon looking closer, I found this:http://i.imgur.com/Xy6f4Yf.jpg
An endless torrent of Merchant Marines was gushing out of the Philippines, sending America into staggering debt with the maintenance costs in the process. Since I had a cruiser by Vietnam, I decided to have it poke around there to see what the hell was going on. As soon as my cruiser touched the port the ships were coming from, they stopped appearing. I dropped some spies to try to figure out where they were all going, and it turned out that a flood of them was arriving in Pearl Harbor. At the same time. Yes the US made a Merchant Marine Conga Line that stretched halfway across the Pacific.
Normally I'd just laugh, but unfortunately, this is causing a major problem. Having so many units around is causing the game to lag to the point of being virtually unplayable (maximum speed now goes about as fast as the slowest speed originally did). I can't be sure because there are so many units there they won't display properly anymore, but it looks like the US has decided to let literally every Merchant Marine it had ever sent from the Philippines stay there. In other words, they aren't going anywhere anytime soon, so I think my savegame may be a bust
I have a backup save file from when the ships were still pouring out if this would be useful for debugging.