diff --git a/src/hotspot/share/gc/shenandoah/shenandoahFullGC.cpp b/src/hotspot/share/gc/shenandoah/shenandoahFullGC.cpp
index 18fd09ead0a..4cef5378d30 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahFullGC.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahFullGC.cpp
@@ -910,6 +910,9 @@ public:
     // Make empty regions that have been allocated into regular
     if (r->is_empty() && live > 0) {
       r->make_regular_bypass();
+      if (ZapUnusedHeapArea) {
+        SpaceMangler::mangle_region(MemRegion(r->top(), r->end()));
+      }
     }
 
     // Reclaim regular regions that became empty