I changed my email on my Academia account that was connected to my StackExchange profile (to my OzEmail account) so I could save the change needed to allow it to be merged with a manual account with the same Gmail account as always otherwise associated with my StackExchange accounts.
The Academia accounts have now been merged. As far as I can see all my accounts (SO, SE, Academia and other random ones checked) still have my original Gmail account. But today I received my VB and VB.NET SO subscriptions on my OzEmail account.
(I have fixed them manually and they required me to confirm the change on my Gmail account. I never received any confirmation on the OzEmail account.)
I'm not sure this is a bug, but it feels a bit like it.