I've heard that from a few travellers in central america. If you're non-american and got a cuban stamp in your passport they'll give you hell in US-immigration.
US-immigration gave me hell even if I hadn't been in Cuba. They didn't like that I didn't have a hotelreservation, destination and plan for my visit to L.A. Go figure
. Took me an hour to get through. The funny part is that they treated me like crap in immigration, but once I was trough they treated me like fucking royalty.