don't know if it is normal or not, i know on my B2400 the fel will leak down and to test my 3 pt one time i left the rear blade a few in. off the ground and 24 hrs. later it had NOT leaked down.
The 3PH and loader on my BX2000 "leak-down" over time. Depending on the weight attached it make take anywhere from a few hours to several days. I think that is normal, at least for Kubota. A friend of mine has a 7800 and it does the same thing.