My phone is an iPhone on iOS 12.1. I had a second phone that was not an iPhone and in my personal contact card on my main phone, I had the second phone number added as an additional entry for mobile number. So my contact card "MyName" had my main mobile number and a second number in it. When I would loan my second phone to my daughter, it would appear as though I was texting myself but it was fine for the time.
Now I've moved the SIM card from the temp phone and put it into an older iPhone and now that phone and number are officially my daughter's phone. I removed the second phone number from my contact card and created a new contact card "Daughter" with that phone number on it.
The problem is that when I text to "Daughter", as soon as the message finishes sending, it switches to show that it is "MyName" instead of "Daughter" and it's back to looking like I'm texting with myself. I've confirmed that my daughter's phone number doesn't show up in my contact card and that my number doesn't show up in hers. And I've confirmed that on the phone contacts as well as in iCloud.com just to be sure nothing is hanging around there. I've tried doing this iMessage off and on and I get the same result.
My daughter's phone doesn't have any confusion - it shows "MyName" when received from me. It's only my phone that is confused showing "MyName" when coming from my daughter's phone. When I tap on the name (and then the "i" and then the arrow next to the name) for a message received from my daughter, it shows my whole contact card and does not include the her phone number in that list. Clearly something is cached somewhere but I can't figure out where that would be to clear it out. Any suggestions short of clearing out my phone and starting over?
Additional Info: I just tried calling from my daughter's phone and my phone showed my daughter's contact info on the incoming call. I also tried calling from my phone to my daughter's phone and it showed her info on the outgoing call. So the phone app has the right contact info but the Messages app is where the problem is.