Cybaster

Hello everyone,
I've had my stock turbo setup in my car for a while, but never really had the chance to figure out whats wrong.

Today when i hit about .7~.8 bars of boost, i see my boost gauge BLOW OFF like what would happen if i let go of the gas completely. but

#1 I have the stock bypass valve in the car
#2 i was trying to hold the boost and my foot was giving it gas
#3 the car didn't really bog or have a vaccum leak
#4 i don't know if this also happened before or after the "blow off" but when i boost above .1~.2 bars i hear a "leaky" sound.


anything wrong anyone could think of on top of their heads?