diff --git a/core/slice.go b/core/slice.go
index f4381d9da5..8fb34a30dc 100644
--- a/core/slice.go
+++ b/core/slice.go
@@ -439,7 +439,7 @@ func (sl *Slice) Append(header *types.WorkObject, domPendingHeader *types.WorkOb
 
 	time15 := common.PrettyDuration(time.Since(start))
 	// Relay the new pendingHeader
-	sl.relayPh(block, pendingHeaderWithTermini, domOrigin, block.Location(), subReorg)
+	go sl.relayPh(block, pendingHeaderWithTermini, domOrigin, block.Location(), subReorg)
 
 	time16 := common.PrettyDuration(time.Since(start))
 	inputs, outputs := block.InputsAndOutputsWithoutCoinbase()