diff --git a/Framework/Geometry/FourVector.h b/Framework/Geometry/FourVector.h
index 93f29dcf8379da8359b76c7d6e218a7ca08b0140..d3fe31f1838e64e052587f474baa2fdc259870bf 100644
--- a/Framework/Geometry/FourVector.h
+++ b/Framework/Geometry/FourVector.h
@@ -63,9 +63,11 @@ namespace corsika::geometry {
       return GetTimeSquared() > fSpaceLike.squaredNorm();
     } //! Norm2 > 0
 
+    /* this is not numerically stable
     bool IsPhotonlike() const {
       return GetTimeSquared() == fSpaceLike.squaredNorm();
     } //! Norm2 == 0
+    */
 
     FourVector& operator+=(const FourVector& b) {
       fTimeLike += b.fTimeLike;
diff --git a/Framework/Geometry/testFourVector.cc b/Framework/Geometry/testFourVector.cc
index 994cd6791def8ab246ef70ee7f505b19c8ffa1b6..301fb97e93d71dccc79fe0eda844376b7ecc133d 100644
--- a/Framework/Geometry/testFourVector.cc
+++ b/Framework/Geometry/testFourVector.cc
@@ -63,15 +63,15 @@ TEST_CASE("four vectors") {
 
     CHECK(p0.IsSpacelike());
     CHECK(!p0.IsTimelike());
-    CHECK(!p0.IsPhotonlike());
+    //CHECK(!p0.IsPhotonlike());
 
     CHECK(!p1.IsSpacelike());
     CHECK(p1.IsTimelike());
-    CHECK(!p1.IsPhotonlike());
+    //CHECK(!p1.IsPhotonlike());
 
     CHECK(!p2.IsSpacelike());
     CHECK(!p2.IsTimelike());
-    CHECK(p2.IsPhotonlike());
+    //CHECK(p2.IsPhotonlike());
   }
 
   /*