diff --git a/flytepropeller/pkg/controller/nodes/array/handler.go b/flytepropeller/pkg/controller/nodes/array/handler.go
index 0918ab6035..4f98e66796 100644
--- a/flytepropeller/pkg/controller/nodes/array/handler.go
+++ b/flytepropeller/pkg/controller/nodes/array/handler.go
@@ -389,16 +389,19 @@ func (a *arrayNodeHandler) Handle(ctx context.Context, nCtx interfaces.NodeExecu
 			arrayNodeState.SubNodeRetryAttempts.SetItem(index, uint64(subNodeStatus.GetAttempts()))
 			arrayNodeState.SubNodeSystemFailures.SetItem(index, uint64(subNodeStatus.GetSystemFailures()))
 
-			startedAt := nCtx.NodeStatus().GetLastAttemptStartedAt()
-			subNodeStartedAt := subNodeStatus.GetLastAttemptStartedAt()
-			if subNodeStartedAt == nil {
-				// subNodeStartedAt == nil indicates either (1) node has not started or (2) node status has
-				// been reset (ex. retryable failure). in both cases we set the delta timestamp to 0
-				arrayNodeState.SubNodeDeltaTimestamps.SetItem(index, 0)
-			} else if startedAt != nil && arrayNodeState.SubNodeDeltaTimestamps.GetItem(index) == 0 {
-				// otherwise if `SubNodeDeltaTimestamps` is unset, we compute the delta and set it
-				deltaDuration := uint64(subNodeStartedAt.Time.Sub(startedAt.Time).Seconds())
-				arrayNodeState.SubNodeDeltaTimestamps.SetItem(index, deltaDuration)
+			indexUint := uint(index) // #nosec G115
+			if arrayNodeState.SubNodeDeltaTimestamps.ItemsCount >= indexUint {
+				startedAt := nCtx.NodeStatus().GetLastAttemptStartedAt()
+				subNodeStartedAt := subNodeStatus.GetLastAttemptStartedAt()
+				if subNodeStartedAt == nil {
+					// subNodeStartedAt == nil indicates either (1) node has not started or (2) node status has
+					// been reset (ex. retryable failure). in both cases we set the delta timestamp to 0
+					arrayNodeState.SubNodeDeltaTimestamps.SetItem(index, 0)
+				} else if startedAt != nil && arrayNodeState.SubNodeDeltaTimestamps.GetItem(index) == 0 {
+					// otherwise if `SubNodeDeltaTimestamps` is unset, we compute the delta and set it
+					deltaDuration := uint64(subNodeStartedAt.Time.Sub(startedAt.Time).Seconds())
+					arrayNodeState.SubNodeDeltaTimestamps.SetItem(index, deltaDuration)
+				}
 			}
 
 			// increment task phase version if subNode phase or task phase changed