ISX crankcase filled with water

[hct5]

alright so we have a engine rebuilt out east, the driver then took it 500 miles and a crankcase code went active and he stated it looked like there was water in the oil. so we have it brought back to the shop that did the work. they pulled the pan and pressure tested the coolant system and said that they did not see anything leaking. they said that the one way check valve in the crankcase housing was stuck closed so they pulled the valve out and send the driver on his way. we get it back our shop and i pull the crankcase filter cover off and half a gallon of water falls out. it dose not look like coolant it looks like moisture. i pulled some oil out of the drain on the pan and it dose not look like there is any coolant in it. also pressure tester has held over night. could the engine have a large amount of moisture in it due to the one way check valve being stuck closed and when they took that valve out and he brought the truck say 900 miles back to us all, the moisture in the engine clogged the filter causing it not escape?