SERVER-135563 changed the readConcern for _shardsvrCheckMetadataConsistencyParticipantCommand from local to majority. Since the command didn't report support for readConcern, the invocation was rejected, which is easy enough to fix by just changing the command itself. In multiversion environments, old binaries can still reject the command with the new readConcern, for that reason the error is tolerated. In the future, once it's no longer possible to interact with such old binaries (i.e. when 10.0 is branched out), those lines can be removed.