diff --git a/packages/font-glyphs/src/common/shapes.ptl b/packages/font-glyphs/src/common/shapes.ptl
index d3fe70507..a8228fc33 100644
--- a/packages/font-glyphs/src/common/shapes.ptl
+++ b/packages/font-glyphs/src/common/shapes.ptl
@@ -432,7 +432,7 @@ glyph-block CommonShapes : begin
 		local doSwash : !noSwash && !isStart && atBottom && (para.isItalic || isTail) && [if (para.slopeAngle >= 0) ltr [not ltr]]
 		local superness DesignParameters.superness
 
-		local y : yRef + [if dtu (-1) 1] * overshoot
+		local y : yRef + [if (yRef > toFinish.y) (-1) 1] * overshoot
 
 		# Adjust terminal's position if necessary
 		toFinish.x = toFinish.x + OXHook * [if ltr (-1) 1] * [if isStart (-1) 1]