The fsm test jstests/concurrency/fsm_workloads/query/invalidated_cursors.js performs createIndex and accepts the following erros as possible results due to concurrent operations.

In case of continuos dropDatabase, the createIndex has been proven to possibly fail with cannoImplictlyCreateCollections. The exception is thrown when the collection does not exists  and is managed internally by the router up to 10 retries. As any other exception, cannoImplictlyCreateCollections still consumes one attempt, and concurrent dropDatabase might be causing the exception to happen often enough to be reported to the user. 

For the same reason, we could be possibly fail with StaleConfig. 

The test should adds to the accepted errors: StaleConfig, cannoImplictlyCreateCollections