So on 8.5 I setup the proper VLANs and enabled IP passthrough on both my cellular connections on my BR2 Pro.
When I plug a device into the proper port the correct public IP is displayed on the computer but if I am to go to an IP checking website - I get the IP of the secondary modem.
What is the proper flow to make sure each port is handing off its own isolated IP passthrough connection?
I now believe this to be a firmware issue. I just setup another dual modem (different hardware type) and the same issue exists with a different carrier. @Lai
Further testing has shown this appears to an 8.5 firmware issue, unrelated to a dual-SIM device. Experiencing the same issue with a B One 5G, when using multiple active wired WAN’s with cellular IP Passthrough.