Boost flactuates at high rpm

[Scol]

Hi everyone,

I am currently tuning the car with an S280 turbo, and when increasing boost, I am experiencing oscillations above 6K rpm.

Wastegate duty cycle is not maxed out yet. Has anyone experienced this and what would be the cause please ?

Thank you



https://datazap.me/u/eas/run-high-boost?log=0&data=1-3

Mods as follows:
S280 Turbo with s280actuator
Ported manifold
3.5" decat and cat back exhaust
2.75" Crossover with ITG Intake