Measured Drain to Source Peak Voltage seems very high on PoE circuit
This is an active clamp flyback converter.  During the switch (Q16) off time the secondary voltage appears across the primary winding scaled by the turns ratio.

That adds to the input voltage.  Finally, the active clamp capacitor charges from the leakage inductance and eventually pushes the drain voltage even higher.  So the peak voltage will be the sum of the three.