diff --git a/GPy/kern/_src/coregionalize.py b/GPy/kern/_src/coregionalize.py
index 3d71c99f..b8e1e139 100644
--- a/GPy/kern/_src/coregionalize.py
+++ b/GPy/kern/_src/coregionalize.py
@@ -94,7 +94,7 @@ class Coregionalize(Kern):
             dL_dK_small = self._gradient_reduce_numpy(dL_dK, index, index2)
 
 
-        dkappa = np.diag(dL_dK_small)
+        dkappa = np.diag(dL_dK_small).copy()
         dL_dK_small += dL_dK_small.T
         dW = (self.W[:, None, :]*dL_dK_small[:, :, None]).sum(0)