I JUST was forced to update my Quicken Classic Deluxe (went to run it and was immediately prompted to let Quicken update my version). R69.26 build 27.1.69.26
I then did an OSU. Got a message CC-800 about my Ally accounts.
OK, I click my Ally Checking account, then click the little gear icon and do Update Now.
Instead of showing Ally as the FI, it shows my local bank (TrustCo).
Sure enough, in the Ally Account details, the FI has been changed to TrustCo Bank.
I'm leery of having to restore from the backup only because it usually totally screws up all the online stuff (forcing you to basically deactivate almost every account and reactivate them and then of course you get months of past transactions you have to manually clear).
Have no idea why the Quicken Update modified the accounts and switch FI on me, but it did.