diff --git a/src/libslic3r/Config.hpp b/src/libslic3r/Config.hpp
index 40c0fc7c5f..13a70455bf 100644
--- a/src/libslic3r/Config.hpp
+++ b/src/libslic3r/Config.hpp
@@ -560,7 +560,7 @@ public:
                 if (diff_index[i] != -1) {
                     for (size_t j = 0; j < stride; j++)
                     {
-                        if (!other->is_nil(diff_index[i]))
+                        if (!other->is_nil(diff_index[i] * stride))
                             this->values[i * stride +j] = other->values[diff_index[i] * stride +j];
                     }
                 }