Different Number

After having this issue and finding no solution I figured it out. 

*On androids with googles messages app*

When activating the sim T-Mobile gives you a temp number if you message someone before your number is swapped Google will register the temp number as your RCS number and it will remain there even after your number is swapped, unless manually changed. 

The change is easy. 

Go into the app - settings - RCS chat, from here turn it off and desync the previous number, add the new number, then wait for the confirmation code and welcome to using your actual number for texting. 

Peaces ✌🏻

Thanks again to everyone that responded. Much appreciated!

This has been so helpful. T-Mobile support couldn't fix it, so I "googled" my question.  It seems that RCS chats are sent two different ways, and if a previous number is stored in RCS chats, then it has to be removed and the new number added. Thank you to all who take the time to contribute to these questions!! 

is it a different number under her contacts in your phone that is coming up or a completely different number entirely that is not in your contacts anywhere?

if you pull up your dial pad and type the number that keeps popping up into the dialer does a contact pop up or does it just show the numbers by itself?

It just shows the numbers by them self. When I call the number I get a message saying that the "subscriber you have dialed is not in service"

all i can really think of would be to fully delete all of her contact info as well as any text or call history so all info about her has been removed from the phone..restart the phone then re add all her contact info back in.. her info might have gotten boogered up in your phone somehow?

only other thing i could think of was are you guys using anything like Digits for messaging? or has her number ever had to be forwarded to a different device/number?

oh and how long have you guys been with TMO? are you super new and the number you are seeing is a temp number?

Thanks for your continued help. I completely deleted her information on my phone, restarted it and there was no change.

Her number has never been forwarded to another number and we’re not using “Digits” for messaging.

We have been with T-Mobile for 1-week as of today.

Does she have a Google Voice number?

Just saw the last line , if you ported you were given a temp number until the port is completed then the real number goes through.