diff --git a/MaterialLib/SolidModels/MFront/MohrCoulombAbboSloan.mfront b/MaterialLib/SolidModels/MFront/MohrCoulombAbboSloan.mfront
index b2348cf0e70555f69ae118f6126ae2ce8df38c50..f9f7bbf7e87e19859975e04a88541899e8efc1b0 100644
--- a/MaterialLib/SolidModels/MFront/MohrCoulombAbboSloan.mfront
+++ b/MaterialLib/SolidModels/MFront/MohrCoulombAbboSloan.mfront
@@ -185,7 +185,7 @@ a.setEntryName("TensionCutOffParameter");
         const auto dev_s_squared = computeJ3Derivative(
             sig);  // replaces dev_s_squared = deviator(square(s));
         const auto dG_dI1 = sin_psi / 3.;
-        const auto root = max(sqrt(J2 * KG * KG + a * a * sin_psi * sin_psi),
+        const auto root = max(sqrt(J2 * KG * KG + a * a * tan(phi) * tan(phi) * cos(psi) * cos(psi)),
                               local_zero_tolerance);
         const auto dG_dJ2 = KG / (2. * root) * (KG - tan_3_lode * dKG_dlode);
         const auto dG_dJ3 = J2 * KG * tan_3_lode / (3. * J3 * root) * dKG_dlode;
diff --git a/Tests/Data/Mechanics/MohrCoulombAbboSloan/load_test_mc.prj b/Tests/Data/Mechanics/MohrCoulombAbboSloan/load_test_mc.prj
index 4c6222cf04148eb5336b4d99d8610eaacc55e21e..00c1fb86b8fb681c656e6e334ae3908b4a919770 100644
--- a/Tests/Data/Mechanics/MohrCoulombAbboSloan/load_test_mc.prj
+++ b/Tests/Data/Mechanics/MohrCoulombAbboSloan/load_test_mc.prj
@@ -345,8 +345,8 @@
         <vtkdiff>
             <file>load_test_mc_pcs_0_ts_40_t_40.000000.vtu</file>
             <field>sigma</field>
-            <absolute_tolerance>1e-12</absolute_tolerance>
-            <relative_tolerance>1e-12</relative_tolerance>
+            <absolute_tolerance>1e-11</absolute_tolerance>
+            <relative_tolerance>1e-11</relative_tolerance>
         </vtkdiff>
         <vtkdiff>
             <file>load_test_mc_pcs_0_ts_40_t_40.000000.vtu</file>