Group Texting

When responding to a group text with one android user, my iPhone 13 phone will respond to the entire group but add 006 to the android users number so instead of xxx-xxx-xxxx it sends the message to 006xxx-xxx-xxxx. Also I cannot individually text the android user but I can text any other non iPhone. The user is a family member and has been confirmed that there is no blocked number with the service provider.

Ive switched out SIM cards, factory reset settings, upgraded from a 12 to a 13 and the issue is persistent