A level 7 valve shouldn't hold air when degassed. The air can escape out the inlet when the air line is removed. Are you using a check valve in your air line anywhere?
If the on-off pin is too short, or if air is leaking around one of the top orings (usually the smaller one), it can go full auto or burst.
Have you checked your bolt spring? If it is weak, it can cause bolt stick and venting. It won't allow the bolt to properly reset.
Have you tried turning up the velocity? A low pressure/velocity can cause weird issues with orings leaking and cycle problems.
Try a ULT with the hyper frame. The ULT doesn't work with the classic valve when used with a manual frame, but electronic frames don't have the same issues because the on-off doesn't have to push against the finger on the trigger.
Except for the Automag in front, its usually the man behind the equipment that counts.