Technical Boost issue

[MyNameIsHate]

Hi guys, i'm a proud owner of a jtd115 stilo and i'm having a problem that is driving me nuts.

I'm having a major boost drop, my car cant hold the correct boost, it spikes to the correct pressure then drops about 0.5 bar, if i release the gas pedal and step on it again it regains pressure.

Sometimes i get the P0236 error code

Changed the boost solenoid
Changed vacuum hoses
Cleaned MAP sensor
Changed intercooler joining piping (i have a front mount)

Can someone please help shed some light?

Thanks in advance