ps_aux on TE0817

[benm]

Hello,
I have a problem powering up a TE0817 module:
LP_DCDC is 3.3V
3.3VIN is 3.3V
EN_LPD is 0
LP_0V85 is 0 as expected
DCDC_2V0 is 0 as expected
PS_PLL is 0 as expected
but
PS_AUX is 0.47V
PS_1V8 is 0.86V
I don't understand how this is happens. I don't use PS_1V8 on my carrier board, it is just connected to a power plane but nothing else is there.
Do you have a hint on what is going on?
Thanks,
Ben