This just started when i installed beta. Not sure if something behind the scences has changed. I noticed that when i text 2 different people with 2 different numbers who both use imessage that when i leave messanger and come back, iMessage has now combined the conversations and i have no idea who im texting. I have deleted both contacts and the message streams, but even wihtout hte contacts in my phone they get combined again. This did not happen with iOS 11 and we have been messaging for years from iOS devices without any problems.
Theory #1: my phone hates me.
Theory #2: iOS12 has changed iMessage. This particular situation is that they use the exact same Apple ID on both devices, and both of there phone numbers are under that apple ID. On one device they have his number checked only. On another devices they have her number checked only.
I understand with family sharing there really isnt a reason to use the same apple ID anymore, however, this is not my device and i have passed along this recommendation to them. But in the mean time once iOS12 public is released, is this a problem they are going to have with all iOS 12 users or is this problem on my end?