My Apple purchase records jumped from true AppleID to one I've never used. This is what I think happened.

I made a rare "Genius" consultation today. The visit confirmed that there's no "safe" Apple-approved way to fix broken glass on an AT&T carrier-unlocked iPhone [1].

That was bad, but along the way we tried checking the devices associated with my Apple ID. That would include several iPhones, iMac i5 27", MacBook Air, iPad, iPods, etc, etc.

Except there were NO devices associated with my Apple ID. All of my registration information was gone. Vanished.

Fortunately the 400+ iTunes purchases associated with that Apple ID appear to be intact [3]. So what happened?

I contacted Apple support who, of course, had no idea what had happened. (I'm sure they thought I was merely senile, but the rep was very polite.) However Apple support's reverse number lookup on the phone I was using brought another of my unwanted four Apple IDs. That AppleID had "lots and lots of purchases".

Except I've never used that Apple ID when doing any kind of purchase or authorization. I always use the (.mac) Apple ID associated with my iTunes account. In fact, I only discovered that AppleID existed about 2 months ago!

So I checked what devices were associated with each of my Apple IDs. I went to Contact Apple Support and chose the Your Products option. This is what I found:

• AppleID (used for all iTunes purchases and for all product registrations and authorizations): 0 items.
• AppleID associated with an old developer account: 18 products going back to 2002 or so.
• AppleID associated with an abandoned MobileMe account: 0 items
• AppleID associated with a now broken iCloud account (formerly working MobileMe account): 0 items

So everything was now under a single AppleID, but it was an oddball AppleID that I've never used anywhere. How the heck did that happen? Why choose that AppleID rather than a complete strangers?

I don't know of course, but the most likely explanation is that the Apple's IT systems are kludged together.

I'm guessing that Apple had one IT systems that was used by iTunes and that an older system used for product registration. At some point in the past the "product registration system's" true "Key" was either a phone number or (more likely) an email address. Recently Apple lashed together the two systems, perhaps attempting to "join" on the email address.

That's where my May 2012 MobileMe/AppleID bug came in

... I've figured out the bug. It arose as a side-effect of changes to the way Apple IDs work, and it only impacts people who are still on MobileMe accounts and who have the same email address associated with two Apple accounts prior to the time Apple made that illegal...

I won't repeat the details of the bug here, but the workaround was to remove an authenticated email address from my primary AppleID and associate it with ... yes... that oddball developer account AppleID. 

I bet, in database terms, that email address was the "Foreign Key" that linked my iTunes controlled AppleID with my Mac purchase records. Moving the email address from one AppleID to another causes the database query to associate purchases with the AppleID I'd moved it to [2]. 

I could try moving the email BACK to my primary AppleID, but I'm afraid I'd lose my purchase associations altogether.

[1] Apple's only approved fix is a refurb substitution. Unfortunately, Apple will replace an AT&T-unlocked iPhone with a locked iPhone, the Apple product database doesn't correctly track AT&T changes to a phone's lock status. After replacement the IMEI does not match AT&T records, so the new phone cannot be unlocked.
[2] Reading my blog post from May I even noticed the problem then, but I was too tired to f/u on it: "Apple's Support Profile is supposed to show the products associated with my Apple ID. I think it used to. I don't see them any more. It says my home number is associated with a different Apple ID..." So maybe my home number was also associated with the moved email.
[3] Apple's iTunes group manages AppleIDs, not the Mac group.