diff --git a/app/core/gimpchannel-combine.c b/app/core/gimpchannel-combine.c
index aaef7918c0..8326f65b0c 100644
--- a/app/core/gimpchannel-combine.c
+++ b/app/core/gimpchannel-combine.c
@@ -455,8 +455,8 @@ gimp_channel_combine_buffer (GimpChannel    *mask,
 
   if (gimp_channel_combine_start (mask, op,
                                   GEGL_RECTANGLE (
-                                    off_x,
-                                    off_y,
+                                    off_x + gegl_buffer_get_x (add_on_buffer),
+                                    off_y + gegl_buffer_get_y (add_on_buffer),
                                     gegl_buffer_get_width  (add_on_buffer),
                                     gegl_buffer_get_height (add_on_buffer)),
                                   FALSE, FALSE, &data))
diff --git a/app/gegl/gimp-gegl-mask-combine.cc b/app/gegl/gimp-gegl-mask-combine.cc
index 5a764de96f..e559283bb0 100644
--- a/app/gegl/gimp-gegl-mask-combine.cc
+++ b/app/gegl/gimp-gegl-mask-combine.cc
@@ -516,7 +516,8 @@ gimp_gegl_mask_combine_buffer (GeglBuffer     *mask,
 
   if (! gegl_rectangle_intersect (&mask_rect,
                                   GEGL_RECTANGLE (
-                                    off_x, off_y,
+                                    off_x + gegl_buffer_get_x (add_on),
+                                    off_y + gegl_buffer_get_y (add_on),
                                     gegl_buffer_get_width  (add_on),
                                     gegl_buffer_get_height (add_on)),
                                   gegl_buffer_get_abyss (mask)))