rollback_fuzzer_[un]clean_shutdowns suites performs restart of nodes between the RollbackTest transition phase. When the nodes are restarted, we only wait until a current primary is elected and available to accept writes in the replica set. As a result, replSetFreeze cmd executed as part of this RollbackTest state transition method transitionToSyncSourceOperationsDuringRollback(), can throw an error if the node restarted is an uninitialized state (not yet loaded the local config or not reached the STARUP2 repl state).