I'm a litt...lot late to this party but as my RPi4 is using PoE I'm able to set the USB-C port to host mode and run the second DAI device that way.
Using the two USB 3 ports I could get two Oak-1-Lites to display live video but as soon as I tried to enable nn on either one I would get this dreaded message on one that fails:
inPreview = qPreview.tryGet()
RuntimeError: Communication exception - possible device error/misconfiguration. Original message 'Couldn't read data from stream: 'preview' Traceback (most recent call last):
Using the below command they're both running nn's.
modprobe -r dwc2 && dtoverlay dwc2 dr_mode=host && modprobe dwc2