Ok, latest update to PMOS seems to have helped this issue. If plugged into a USB 2.0 port it is now detected during boot / reboot. Still won't work if plugged into a 3.0 or 3.1gen2 port, it appears very briefly then you only get to charge.
I'm having a similar issue, but in my case I have even bluetooth and wifi disabled along with usb.
[ 27.743366] modem-power serial1-0: QCFG 'wakeupin/level' is '0'
[ 27.755288] modem-power serial1-0: QCFG 'ApRstLevel' is '1' (changing to '0')
[ 27.779290] modem-power serial1-0: QCFG 'ModemRstLevel' is '0'
[ 27.791309] modem-power serial1-0: QCFG 'apready' is '0,0,500'
[ 27.803274] modem-power serial1-0: QCFG 'airplanecontrol' is '1,0'
[ 27.815301] modem-power serial1-0: AT command 'AT+QCFG="fast/poweroff"' returned ERROR
[ 27.839310] modem-power serial1-0: powered up in 18476 ms
[ 31.715157] vbat-wifi: disabling
[ 31.715197] avdd-csi: disabling
[ 31.715260] usb-5v: disabling
Anyone here found a solution as to why it is disabling and how it can be enabled? Thanks