Added new user without last name, text goes to another user with the same name

[fathergll]

This is a weird one. I have two contacts in my ios 10

Contact 1 - John Smith
Contact 2 - John

"Contact 1 - John Smith" was added a year ago and i have a text message thread with him.
"Contact 2 - John" was just added today.

When I go to send a message to just "Contact 2 - John" it send the message to the earlier thread from "Contact 1 - John Smith". Does anyone know why this would occur? I even deleted "Contact 1 - John Smith" from my phone before I sent the message.

 

[vmachiel]

Simplest would be to add a last name to contact 2. Just call him John 2

 

[GreyOS]

Have you put the same number on both