This happened a few times to me now. Apply throttle in 3rd or higher gear in an rpm range where desired boost (75kpa) can easily be reached. Boost ramps up and hits overboost protection at 95kpa. This happens running just off the wastegate (internal) on a Garrett T28, with essentially 0 pre-laod on the actuator. No EBC or similar shenanigans. No kinks or other problems in the hose leading to the WG. Once overboost protection kicks in, boost settles down and stabilizes.
Is there any way to fix this, other than a new turbine housing with WG?