Apple has clarified a an iMessage "bug" that was reported earlier this week, and involved the intertwining messages from an Apple Genius employee and a customer who brought their iPhone in for repair. Turns out that it was a slip-up on the employee's part. The Loop reports:
“This was an extremely rare situation that occurred when a retail employee did not follow the correct service procedure and used their personal SIM to help a customer who did not have a working SIM,” Apple representative Natalie Harrison told The Loop. “This resulted in a temporary situation that has since been resolved by the employee.”
Apparently, the Apple Genius went the extra mile by inserting his own SIM card into the iPhone because the owner didn't have a working SIM. This resulted in the customer's iPhone being paired with the employee's number, where all texts sent to/from the employee where also being delivered to the customer's iPhone. This issue is similar to the way lost or stolen iPhones using iMessage behave after paired to a specific SIM.
If the employee in question had of simply switched iMessage functionality on and off while his SIM was inserted, or just used a different SIM card, this all would have been avoided. Then again, it looks like the iMessage protocol still needs some adjustment.