I switched from my iphone SE 2nd gen to the 16 pro.

I switched from ATT to Xfinity Mobile

when I set up the phone, I signed in with my icloud, didn't transfer anything and set the phone up as brand new.

I accidentally noticed that on my old phone (which is only working on WIFI/SOS), it receives more complete imessages in group chats than the 16 pro which is active with my Cell Service.

I thought it was a one time blimp, but a couple of days went by, hard reset, signed in/out of icloud, and the issue is still there. I have both phones open on messages app and I can clearly see that i am missing messages on the 16. I also see messages missing on the old phone as well. when I send a message on either phone, it sometimes pops up on both, sometimes just one.

this is very confusing and I've contacted apple several times about it. just curious if anyone has ever dealt with this EVER