iMessage Messages for one contact disappearing
I have a single contact where their messages are disappearing right after sending/receiving and I have no idea what is going on. I can send them a message and they receive it and can respond. I'll see their response in my notifications but when I click (on my Mac) or tap (on my iPhone) it's a blank chat. Upon returning to the messages main screen, I see the conversation fly down the list and disappear. I've deleted the thread by sending a fresh message to them which shows the message in the main messages screen until they reply. I've also deleted their contact from my contact list. I've rebooted everything. I'm at a loss, any ideas?
iPhone 13 Pro