diff --git a/dune/tectonic/ellipticenergy.hh b/dune/tectonic/ellipticenergy.hh
index 274d8c4c8ef09886aa5fca8efe10e4079e749009..df56a85c2dfae664a13bdfbf5c8f7a3a2af582b7 100644
--- a/dune/tectonic/ellipticenergy.hh
+++ b/dune/tectonic/ellipticenergy.hh
@@ -63,7 +63,9 @@ template <int dim> class EllipticEnergy {
       ret = mg;
       ret *= -1;
     } else {
-      assert(false);
+      ret = SmallVector(0);
+      // FIXME: This can happen due to numerical instability
+      // assert(false);
     }
   }