Anyone else ever see a Schema become corrupt?

I have a Revit add-in that stores data using Extensible Storage. For the vast majority of my customers, everything has worked great.

I have one model where the Schema has become corrupt. When I run Entity.Get, Revit throws an ArgumentException error with the description, "The Field belongs to a different Schema from this Entity, or this Entity is invalid."

I was curious if anyone else has seen this error before in a model.

I have tried using Schema.EraseSchemaAndAllEntities() to remove the schema and then recreate it. The recreated schema fails in the same way. The model appears to be unrecoverably broken.