A quick circuit analysis shows that
Vx = Vo + 2(Vfb*R1/R2 + Vbe)
Where Vx is the voltage in question, Vo is the output, Vfb is the feedback voltage of Lt8612 (0.97V), R1 =1K, R2 =4.99K, and Vbe is base emitter voltage of Q3 PNP.
Hope this helps.
Best,
Mike