Here is an update:
TLDR: Switching o-rings and cleaning the reg fixed the problem.
When the original problem started it was caused by bad o-rings or poor o-ring matching. As such, switching back in the stock bolt fixed the problem.
After shooting a few more cases through the stock bolt I tried to re-tackle the problem by switching out all of the o-rings on the drive and bolt. this helped to an extent, but the consistency was really really bad.
Switching back to the stock bolt didn't help this time, so I cleaned and lubed the regulator and everything worked money after that.
Switching back in the goldbolt with the new orings and clean reg == it worked fine.
Please check out my most recent paintball video "CrownPB - 2012" it is only 3.5 minutes long and well worth your time. I am very grateful for every view I get and always appreciate feedback.
CrownPB - 2012
Click here to watch
2012: Hello Nasty - D5 NPS Series Champions and two time 1st place finishes
2013: East Coast Vengeance