Info on the car's recent mods:
Silicone vacuum line job (problem started 2-3 months after the install, should be unrelated)
~60,000 mile charge relief valve installed today
~72,000 mile twin-turbos purchased from Fritz Flynn, very minimal shaft play.

Situation:
Instant 11psi on WOT, transition at 4,000-4,500 brings it down to 8psi.
Car instantly builds back up to 11psi after transition. Then it never fails at 6,000RPM the boost shoots down to 5psi all the way through the rest of the RPM and never builds back up.

As soon as the car hits the 5psi wall, air is dumping out of the CRV, I know it's the CRV because if it's routed back to the airbox the sound isn't heard, vented to atmosphere makes an extremely noticable leak.

I thought that by replacing my 115,000 mile CRV it might fix it, it was worth a shot I guess. But it still does the same thing, and now I'm leaning towards the control system like the Switching solenoid or the likes. What's weird to me is the fact that it holds boost just fine after transition until that magical 6,000RPM comes along.

What do you guys think, what does this sound like to you?

 

sounds like ya solved it already

 

But I have zero experience with solenoids going bad, my first thoughts were that if a solenoid was bad it would stick open 24/7 leaking boost as soon as secondary came into the picture.