I received the message that app store changes required logging out. Haven’t been able to log back in since. The mobile app finds my Ha instance and prompts with the Nabu Casa address but then I get the Object mapper serialization error. Tried brute force method https://companion.home-assistant.io/docs/troubleshooting/resetting it didn’t change anything. I have default_config:, ios:, cloud:, mobile_app: and discovery: in my configuration.yaml. Resorted to webpage display on phone and have lost notifications.
I am in the same boat. I added one phone back in copying the url off the other and now HA is all confused on which phone is which. Yes I realize my error on top of the app store. Now I am looking how to get them signed out to sign in properly.
OK my fix was located in config persons