Datastore how to get past sync errors?

Caram, have you found a way to reproduce this error? It's almost certainly a bug in the SDK, but we haven't had luck reproducing it.

Information that might help: which version of the SDK are you on? Are you using local datastores (and then migrating)? Can you share the code/steps that created and modified this datastore? Did you set a title on the datastore and then remove it?

As to your more general question, it's hard to recover from an error like this. The server is correct that the client is sending an invalid delta. The client doesn't know what to do in this case, because it thinks it's sending a valid delta. Doing something drastic like throwing away the local changes (e.g. what happens when you reinstall the app) can easily lead to data loss. There are other possibilities, but fundamentally this is a bug in the SDK that needs to be fixed. I just don't know how to track it down without being able to reproduce it.