Upgraded to 2.15, permissions aren't picked up


I’m getting the following error in my PROD instance:

You are logged in as 'ABC' but it seems you don't have any permission set in Piwik.
Ask your Piwik administrator (click to email) to give you 'view' access to a website.

I’ve gone through the database manually, ABC seems to have the right records assigned in the tables to get permissions, for both regular user and admin.

My instance works fine in DEV and TEST. The only difference between the DEV/TEST DB and PROD DB, is the engine type. In DEV/TEST, I have MyISAM, in PROD it’s INNODB. At the moment, I fail to see why this difference exists. Otherwise, a schema comparison reveals that they are identical.