diff --git a/src/main/docsrc b/src/main/docsrc
index 3cfb0052ec..ea2a79524b 160000
--- a/src/main/docsrc
+++ b/src/main/docsrc
@@ -1 +1 @@
-Subproject commit 3cfb0052ec8c6a52f04a0aa4f522a6cf75841ad5
+Subproject commit ea2a79524be7750497a306816c3de793dcbff426
diff --git a/src/main/java/org/dita/dost/writer/KeyrefPaser.java b/src/main/java/org/dita/dost/writer/KeyrefPaser.java
index 4aef5b33d8..6e1e90dcfa 100644
--- a/src/main/java/org/dita/dost/writer/KeyrefPaser.java
+++ b/src/main/java/org/dita/dost/writer/KeyrefPaser.java
@@ -211,6 +211,9 @@ public void setKeyDefinition(final KeyScope definitionMap) {
    * Get set of link targets which have normal processing role. Paths are relative to current file.
    */
   public Set<URI> getNormalProcessingRoleTargets() {
+    if (normalProcessingRoleTargets == null) {
+      return Set.of();
+    }
     return Collections.unmodifiableSet(normalProcessingRoleTargets);
   }