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This is what i have right now, my Mac 820-01401A
on UB300 and UB400 20.2v with 110mA .
on U3200 and U3100 5v with 380mA-390mA.
i guess that the 1.1v_LDO rail of the 19.5v is present and in the other ( 5.17v) is not.
Did you check for short on the 1.1V_LDO rail ? Does the other LDO voltages of the ACE are presents ?
edit: Now i see that its on the same side different USB C port . But as i see it , the one with the 20V is the Master ACE chip and the other one is the slave .
so maybe you have a problem in communication between them.