Is the car mapped to run 1bar of boost ?
Did you fit a fit a banjo bolt with a 3mm hole for the oil feed to turbo?
Did you prime the turbo with oil before starting engine ?
The turbo seal is leaking, either it's damaged or there's pressure building up from the oil not flowing out of the turbo.
Check there's no kink on the turbo oil return pipe.
Also check the cam breather pipes aren't blocked.