diff --git a/engine/src/core/com/jme3/math/Ray.java b/engine/src/core/com/jme3/math/Ray.java
index 91d39f1eb..a70d9c93d 100644
--- a/engine/src/core/com/jme3/math/Ray.java
+++ b/engine/src/core/com/jme3/math/Ray.java
@@ -231,6 +231,7 @@ public final class Ray implements Savable, Cloneable, Collidable {
             dirDotNorm = -dirDotNorm;
         } else {
             // ray and triangle/quad are parallel
+            assert vars.unlock();
             return false;
         }