Unable to receive 2FA codes via text with WIFI Calling after updating to iOS 18.5

This has been reported in 2024 with 18.1.1 upgrade. All past descriptions fairly accurate.

When using ATT WIFI Calling texting works, SMS, all messaging works on messaging app.

Area has no cell service and prior to SW upgrade 2FA and short code messaging worked. Now 2FA and short codes don't get through until I drive to an area with cell service and then all short code messages appear.

Short code messaging is used mostly for marketing messages - when you see a "22415" type message that's a short code message or when you use Two Factor Identification "2FA" this is when you tell your bank, your utility, Amazon, or other websites that offer additional security (PayPal, SCE, etc.) to not only log you in but also send you a code via text that you paste into a "code" field onscreen. On Apple Mac the software sees the text come in and offers to paste it automatically into the "code" field for you. That is, if the messages app receives the short code message.

But now this is not working with WIFI Calling. Is this an ATT problem? Perhaps but why did it start when we upgrade our Apple iPhone?

I have asked repeatedly for ATT to solve it with no luck.

Of course I have been through all the suggestions from everyone...reset network, reset all the phone and messages settings, install a new Esim, etc.

Anyone else have any new insights on this?