There is a potential problem after migrating from 11.x to 12.x or after backporting the changes from to a 11.x instance:SAK-32296
- On a 11.x instance, create a user and add it to some sites.
- Login with this account.
- The sites are not in the user's favourite sites (this is fine).
- On a 12.x instance (with the same database).
- Login with the same account.
- All sites are automatically added to the user's favourite sites (if the user is in 100 sites, all 100 sites will be added as favourites).
This will also happen with old users and sites.