I don't know how you store your BH when you take it off, but if you have the stabilizers up, next time drop them down before you try to hook up. That will relieve pressure if you didn't get it all out.
When you're going to unhitch, it helps if you not only move the BH controls around to relieve pressure, but have the loader up, turn off the tractor, and then lower the FEL and operate all its functions as well as the BH functions. You won't have any pressure left.
I actually take mine off with the stabilizers down, then before I disconnect the hoses, I raise them back up once I have it stable on the pad. Before I hook up again, I let the stabilizers back down.
John