Defective powerboard (easy fix) or worst case scenario loose contacts under the SoC (needs reballing).. Powerboard can be easily fixed by replacing bad capacitors. Reballing needs specialistic equipment…
Have all the voltages across the whole board. Must be some problem with some chip... i´ll try to reheat the chips with flux and then we will see. Before i had som problem with a mosfet and that one i changed and it worked after that. But now all the mosfets are ok.