Whilst drumsfield is correct in everything he says, I'd bet Patrick probably identified what you are doing (wrong....sorry).
I think pulling slightly back on the trigger is probably a common thing to those new to double-action a/b's. It was for me.
Whatever the cause, your paint is going on too dry and it is not the paint's fault.
You have great advice above from both drumsfield and Patrick. You're going to be fine.