My JDM informed me that TI FAE review the design and agree to allow MCU MSP430F using the same GND with TPS23882RTQR PoE PSE controller on 54V primary side, and this voltage is main source for PoE PSE power to PoE PD.
I'd like to know why TI FAE okay with that because 54V rail will get most surge coming from AC source to AC/DC and from PoE PSE ethernet front-end.