Thanks for the report. I will look into it and see what the problem is. In the meantime, let me know if you find out anything further about how to reproduce the problem (or if you discover a way around it – either way it could be an added clue to the real problem).
Is this a new iphone that you transferred data onto from your old phone? If so, what process did you use to transfer data from the old phone to the new phone? Did you use iTunes or iCloud? It may be that you did not transfer the data necessary to decrypt games saved on your old phone. In order to open games saved on another phone, your new phone would need the old phone’s keychain data. Depending on how you performed the transfer, this may not have happened.
I used iTunes to transfer data from iPhone 7 to iPhone Xs.
Unfortunately, I reset my old iPhone, so I cannot access any “old” keychain data any more. I guess, I lost my old saved games? Or is there a way to restore them anyway?