[Yetti]

see this all the time.
First off even if the engine was off the hydro boosts accumulator hold about 5 pedal pumps worth of effort.
I believe what you guys are seeing is the bad master cylinder. if you apply the brakes very slowly its like you can step past the pedal effort of normal brakes?
when you step on them or jab them as you apply they work normal?

I suspect the seals and bore are wearing. I see it more on Burbs but its the same. the bore wears where the most action is. the problem with that is the seals wear also. when the seal lip is worn to where it can't expand and follow the shape of the bore it lets fluid slip by. that's what your seeing. when you jab the brakes you expand the seals enough to catch fluid and work normal.

replace the Master cylinder and things should be normal again.