It may try to recover up before shutting down on the 1079. You can test it by just closing the ball valve on a run down. It’s possible that it’s a bad contact on one of the 2 down slow relays so it stops as soon as it drops high speed trying to slowdown to stop at 2. I wouldn’t screw around much more before getting weight out and checking down high speed and setting the rupture to the upper end of the acceptable range. It’s way too common for someone to increase the down empty speed on an I2 valve not knowing how the down fast adjustment works. I remember having to let the inspector decide if he wanted 150 full, 125 empty or 180 full, 155 empty. Been a while, not sure if those numbers are right but that’s roughly how I remember the down adjuster working. I just recently had 3 cars trapping people with 1079s and found out a consultant wrote up the down speeds so the mechanic sped them up.
