"Mixed phone number/id on same apple id: We just updated but phone numbers on the same Apple ID are mixed up now. My son number says it is my daughters. I show up at my son on text. How do I fix this?"
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Item Mixed Up After Updates:
A. Restart your Devices:
whenever you make any major charge to your iPhone, such as an update installation, you should always perform a restart. That way, things will be as they should. Go Here: Restart your iPhone - Apple Support
B. New iCloud Sessions:
Log out of iCloud on both iPhones, and then log back in.