Originally Posted by Bobby_M
Some kegs happen to seal better than others. I'd strongly recommend using a silicone lid gasket and use keg lube to ensure a seal without having to use a burst of CO2 to seat the lid.
That is an excellent suggestion.
I did a writeup on the issue some time ago. I believe it is an issue with used kegs that have suffered some abuse.
You might want to take a look at my writeup on the issues:
Keg Lid Geometry & Adjustment
I really hope that it helps you.