I posted a question about the same fault in 2017 - cant remember if I got a fix on it then but the same fault has come back to haunt me on 2 separate but identical vehicles as below :

I have this fault that returns after a short road test, i seem to think it logs the fault on overrun but not all the time. I have smoke tested the intake, checked EGR and throttle flap, replaced AMM with a genuine one and reset AMM, Throttle and EGR parameters. Live data has been recorded while driving and no drop in signal can be seem when fault logged, actual and desired boost pressure, EGR position and turbo position all correct.

Anybody had anything similar, had plenty of these on normal transits and always a boost pipe leak but cannot find one on this ?