Apple now says you have to have iPhone turned on to get iMessages on all devices? iMac Pro - 10.15.3, iPad 13.3 and iPhone 13.3.1. This AM I noticed that when I did some logging in to different sites, that I have text message 2 step verification turned on, I was not getting the iMessage verification code. Tried multiple sites and times - no iMessages. So, I had to get the codes via iPhone.  I was using an iPad and I got no iMessage on it or my MacBook Pro.  Later on I went to the kitchen and turned on my iPhone and viola, I get all these iMessages with codes coming through which then all go to my other devices.  In talking to Apple the senior tech she tried to get me to update my devices - which I refused - gonna wait a bit on that - but she also said you have to have the most current software on all devices and have all devices on or text forwarding won't work. 

This makes no sense to me.  Anyone else having iMessages not forwarding issues?
so it happened again with the bank agin this am - phone turned off, no verification iMessage received on the iPad or computer even though at about the exact same time I received some iMessage/texts from others....  I decided to call the bank this time and not apple.  The banks response seems reasonable------

the message they send are what the guy called, short code carrier messages and bc the associated number, my cell, was turned off the message is not received and therefore cannot be synced through iMessage to other devices. Makes more sense than what apple told me.