During migration, oplog entries generated by transactions are converted to type 'n' no-op entries and sent to the destination side. These new oplog entries also retain the original fields, like 'ns' and 'uuid'. If the collection with the same name is drop and re-sharded, the secondaries will trigger an fassert when processing this type 'n' entries because the uuid no longer exists.

Example log in secondary:

Fatal assertion 16359 NamespaceNotFound: Failed to apply operation due to missing collection (32c50ae4-cec3-4f80-b70a-d1a60a74835c): ...