Do not process txns if node out of sync (#3958)

* Do not process txns if node out of sync

* fix rpc test

node/node.go

@@ -195,6 +195,12 @@ func (node *Node) tryBroadcastStaking(stakingTx *staking.StakingTransaction) {
 
 // Add new transactions to the pending transaction list.
 func (node *Node) addPendingTransactions(newTxs types.Transactions) []error {
+	if inSync, _, _ := node.SyncStatus(node.Blockchain().ShardID()); !inSync && node.NodeConfig.GetNetworkType() == nodeconfig.Mainnet {
+		utils.Logger().Debug().
+			Int("length of newTxs", len(newTxs)).
+			Msg("[addPendingTransactions] Node out of sync, ignoring transactions")
+		return nil
+	}
 	poolTxs := types.PoolTransactions{}
 	errs := []error{}
 	acceptCx := node.Blockchain().Config().AcceptsCrossTx(node.Blockchain().CurrentHeader().Epoch())