Both DonorStateMachine and RecipientStateMachine call resharding::clearFilteringMetadata() which will clear the filtering metadata for the source namespace and temporary resharding namespace for all active resharding operations. Today, there can only be a single resharding operation active in the cluster at any one time but that restriction is intended to change in the future.

• https://github.com/mongodb/mongo/blob/774fe7d3a26749f9b71d17c8a5952ab412f3b2b0/src/mongo/db/s/resharding/resharding_donor_service.cpp#L179-L181
• https://github.com/mongodb/mongo/blob/774fe7d3a26749f9b71d17c8a5952ab412f3b2b0/src/mongo/db/s/resharding/resharding_recipient_service_external_state.cpp#L183-L185