diff --git a/src/truetype/ttgxvar.c b/src/truetype/ttgxvar.c
index 8fda112b0..e51dd4a4a 100644
--- a/src/truetype/ttgxvar.c
+++ b/src/truetype/ttgxvar.c
@@ -1366,8 +1366,12 @@
     {
       FT_Face  root = &face->root;
 
-
-      if ( face->os2.version != 0xFFFFU )
+      /* Special case for varying ascender, descender and height: Only modify if
+       * OS/2 fsSelection's USE_TYPO_METRICS is set. sfnt_load_face uses the hhea
+       * metics by default, this code would otherwise blindly overwrite those
+       * metrics with typo or win metrics, leading to a difference in metrics for
+       * default outlines and all instances. */
+      if ( face->os2.version != 0xFFFFU && face->os2.fsSelection & 128 )
       {
         if ( face->os2.sTypoAscender || face->os2.sTypoDescender )
         {