I'm having problems right now with an SNA applied to SR Bangkok reservation after the migration.
This is just a theory, but I believe we have a pervasive IT error, which results in "confirmed" SNA upgrades reverting back to original room type. Then, even if the property tries to make it right, they don't know what rooms you selected for upgrade, so even if they try to do the right thing, the result may not be consistent with the original SNA request (i.e., you get a room type you did not select). Based on my experience at SR NYC, it's also possible that the IT error reasserts itself, so every time the property upgrades you, the system then downgrades you again.
It's a truly lovely way to "reward" your best customers.