Exception occurred when persisting state to the database

I have seen this error occur for more than one reason, but today was a new one for me. In the Application Event Log, an error for a suspended orchestration states:

Inner exception: Exception occurred when persisting state to the database.

Further down, it gives a little more detail, but it is still unclear what caused the error:

A batch item failed persistence Item-ID b3a8257e-c840-4f91-88da-a41b00c7333b OperationType MAIO_CommitBatch Status -1061151960 ErrorInfo An error occurred when accessing the part data or one of its fragments. The part data or fragment may not exist in the database.

Turns out it was related to a map. The root cause of this error was that the map was generating output that was invalid according to the output schema. Sure enough, I tested the map with the message from the suspended orchestration, and the output was invalid. Once I changed the map and it passed testing, the error did not occur.