Dual SIM Group Message Bug

RockyHasMacProblems wrote:

Iphone 16 Pro Max

Dual SIM (purchased in HK)

iOS version 18.5

US carrier: T-mobile

Intl carrier: Chonghua Telecom

My old iphone 15 plus worked with just a virtual sim. then I switched to a dual SIM. I shifted my US which was primary to secondary for voice and data. I had a pre-existing group chat. When a person in the group chat sends a message to the group chat, on my side, it shows as the message being sent directly to me, and when I respond to the group, the message shows up to each group member as my direct message to that group member. I received a "hey, you messaged me instead of the group" from multiple group members. And I also see all group member's group messages as individual direct messages to me (the content is clearly meant for the group chat). This is likely a bug caused by the iphone not knowing which SIM I am on and the group message not tagging or identifying my alternative number correctly. This is happening only for group chat. Please replicate and fix this bug.

MMS is your phone carrier feature not Apples. You'll need to sort it out with them whether it's Tmobile or Chongua Telecom.