diff --git a/src/hb-ot-shape-fallback.cc b/src/hb-ot-shape-fallback.cc
index f3308847e..458c8eaa0 100644
--- a/src/hb-ot-shape-fallback.cc
+++ b/src/hb-ot-shape-fallback.cc
@@ -218,10 +218,10 @@ position_mark (const hb_ot_shape_plan_t *plan,
     case HB_UNICODE_COMBINING_CLASS_DOUBLE_BELOW:
     case HB_UNICODE_COMBINING_CLASS_DOUBLE_ABOVE:
       if (buffer->props.direction == HB_DIRECTION_LTR) {
-	pos.x_offset += base_extents.x_bearing - mark_extents.width / 2 - mark_extents.x_bearing;
+	pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width / 2 - mark_extents.x_bearing;
         break;
       } else if (buffer->props.direction == HB_DIRECTION_RTL) {
-	pos.x_offset += base_extents.x_bearing + base_extents.width - mark_extents.width / 2 - mark_extents.x_bearing;
+	pos.x_offset += base_extents.x_bearing - mark_extents.width / 2 - mark_extents.x_bearing;
         break;
       }
       HB_FALLTHROUGH;
diff --git a/test/shaping/fonts/sha1sum/856ff9562451293cbeff6f396d4e3877c4f0a436.ttf b/test/shaping/fonts/sha1sum/856ff9562451293cbeff6f396d4e3877c4f0a436.ttf
new file mode 100644
index 000000000..23da109f1
Binary files /dev/null and b/test/shaping/fonts/sha1sum/856ff9562451293cbeff6f396d4e3877c4f0a436.ttf differ
diff --git a/test/shaping/tests/fallback-positioning.tests b/test/shaping/tests/fallback-positioning.tests
index 3eace30c8..86f5640c2 100644
--- a/test/shaping/tests/fallback-positioning.tests
+++ b/test/shaping/tests/fallback-positioning.tests
@@ -1 +1,2 @@
 fonts/sha1sum/8228d035fcd65d62ec9728fb34f42c63be93a5d3.ttf::U+0078,U+0301,U+0058,U+0301:[x=0+1030|acutecomb=0@-21,-27+0|X=2+1295|acutecomb=2@-147,320+0]
+fonts/sha1sum/856ff9562451293cbeff6f396d4e3877c4f0a436.ttf::U+0061,U+035C,U+0062:[uni0061=0+512|uni035C=0@-64,-128+0|uni0062=2+512]