My mom and I just updated our phones to iOS 12. She has the 8 and I have the X. We have a group message chain that includes our entire family. On Monday, we stopped receiving messages in the chain from my sister. We can see the responses from everyone else. We can send and receive texts when we text her individually. So she has been sending what she sends to the group to my mom and I separately. I was wondering if this a known issue with IOS 12. Or maybe a glitch on my sisters side. I called T-Mobile for help and they walked me through some troubleshooting steps, but nothing. Thanks