I have been using iPhone 11 (BYOD) for over a year now with FIDO. Recently to check something, I used ny old device (Pixel 2) by inserting my same FIDO SIM. After that whe I put SIM into iPhone11 back, I realized I was not getting any text messages at all, though I could send. Surprisingly I still receive SMSes on my pixel 2 which even does not have a SIM in it (it is connected to my home WIFI).
I did everything turnin off/on iPhone 11, iMessage turn on/off, googled anything available on internet but problem did not resolved.
I am not even sure if this is a FIDO issue or iPhone issue?
It's definitely a strange situation! Since you are receiving SMS on your Pixel 2, it could mean that something is activated on that device and that would be why the text messages are still directed to it and not your iPhone 11.
Can you confirm if your RCS messaging (Rich Communication Services) is turned off in your Pixel 2 settings?
You should be able to find that in your text message application.
Also if you remove the WiFi connection from your Pixel 2, does it persist?
Let us know 🙂