iPhone keeps re-associating with old Apple ID after restart
I had a phone tied to my current Apple ID. I gave that phone to a relative, and at the time that relative created their Apple ID and added it to the phone while my Apple ID was still the primary email. Meaning that, for a bit, that phone was still tied to my Apple ID.
Note that at the time I was signed in on my personal phone with my Apple ID as well, therefore two devices were using that ID as the primary email.
After removing that Apple ID from the relative’s phone, and adding their own Apple ID as the primary email, every time they power their phone down and then power it back up, they are prompted to verify their phone using a code sent to my phone. After this, that device is once again added as one listed under my Apple ID.
Both me and said relative prioritize our privacy, so we do not wish to have devices and Apple IDs that are not our own associated with our personal use.
Can anyone assist me in remedying this? Has this happened to anybody else?
iPhone 13, iOS 26