[spurviance]

I recently transferred a Belgian Quad to a 5 gallon corny keg after 18 days and FG stabilized for the last 3 days.  I added a small dose of priming sugar in hopes it will naturally carbonate while I let this beer condition until next fall.   There is about an inch headspace in keg which I pressurized to 12psi in order to purge some O2 and  to verify spunding valve works.  Over the next 24 hours the pressure gradually fell to zero.  I repressurized keg and sprayed keg to look for leaks, seeing none. 
Is it possible for small amount of CO2 in the headspace to be absorbed by the beer and resulting in a loss of pressure?  Or do I simply have a tiny leak that I'm not detecting.   This keg recently held CO2 pressure for 2 weeks after forcing out starsan so I was pretty confident that this keg was in good shape.

[MNWayne]

The pressure in the head space is being absorbed into the beer.  Williams Brewing sells oversize lid gaskets which give a great seal, perfect for natural carbing.