I ran an H60 on my AMD 1090T for about 2 months without many problems. The cooling ability wasn't fantastic and I was unable to reach 4Ghz at safe temps, so I upgraded to proper watercooling afterward.
When I removed the H60 though I noticed some water droplets had formed around the shroud of the exhaust fan, and now with it out of the case it is quite obvious from shaking the radiator that there is air inside.
Are they meant to be completely full of liquid with no air at all, or is it normal for some air to remain in the top of the radiator like with a reservoir?
I'd like to re-use it again in my housemate's computer to replace his stock cooler but want to make sure its not dead already.
But it sounds like yours somehow started purging itself of the liquid. Is it kind of oily with a slight aroma of antifreeze? Only reason I ask is some people have mentioned that the H50 has antifreeze in the loop.
If I were you though I would take no chances and RMA it.