Hmmm, good one. I believe I'd pull the motor, if for nothing else, to check the condition of the shaft key. If there's a problem with the shaft key, I'd like to know about before it gets worse. As for the relief changing, I suppose it's possible. Everytime the paddles hang, for whatever reason, you'll be cramming oil over the relief. Done enough times, I suppose it's possible the relief spring begins to loose some strength, making the pressure to open it go down. You could try adjusting it a little, but it's hard to know where your at without a pressure gauge connected to the circuit so you can set it to the recommended pressure. Adjusting the relief all the way in prevents the poppet from lifting off the seat. I think they are recommending this if the paddles won't turn at all. I'm not sure it applies to weak power with material in bucket. You could adjust it in until it bottoms out, then back it out maybe a half a turn, this should give you some relief under load.