I have had good luck with the Indy covers too. Use them for a lot of engines actually.

Do you kill the engine at the stripe or not?

Yes, I always kick it to neutral and kill the engine..

Sounds like Indy may be the way to go..

Dave

I don't know that this plays into anything at all but I am the same, kill the engine in the lights. We speculated that my issues may have had something to do with it as well. Mind you my issue was with a KB pump but still wondered if it was a factor at all...I had it happen to two different pumps and we tried various remedies. Finally just changed the pump never had an issue after that.

I would also inspect the area of the relief port (leading from the retracted valve position either to the LP side or to the pan). I suspect many aren't large enough to dump quickly especially with high viscosity and pressure. Some automotive pumps allow the piston to retract way past the port edge, meaning the port could be extended backward (examine the casting to be sure there's enough metal, duh). I wouldn't try to enlarge the circumference for exactly the reason mentioned: stability in the passage may be compromised.
In the Chevrolet L6 pump I'm working on now, the port is only 61% as large as the passage, the piston's OD is about 80% covered by the casting.

There has been some back & forth about why/when to dump excess back into the feed side as opposed to right into the pan: relief oil to the LP port causes turbulence at the inlet and may aerate flow? Not sure when this happens.

IMHO it's possible, lots going on.
OTOH it's reading from the sender - how far is that away from the relief valve? Even if it makes you nervous it may not reflect any change in the main gallery.