Why does gmail history list api return invalid identifiers?

Question

I do the synchronization work with the client as an official guide .

When performing partial synchronization, why does history.list api return some identifiers that cannot be obtained from messages.get api? messages.get api will return

 { errors: [ { domain: 'global', reason: 'notFound', message: 'Not Found' } ], code: 404, message: 'Not Found' } 

I get the same result in google api explorer.