No ticket. Optimize top/left hooks: move the position check up, don't re-check it inside a hook.

src/css.js

@@ -589,15 +589,14 @@ jQuery.each( [ "top", "left" ], function( i, prop ) {
 				return;
 			}
 
-			if ( pixelPosition ) {
-				// Hook not needed, remove it.
+			if ( pixelPosition || !jQuery.fn.position ) {
+				// Hook not needed or impossible to apply due to a missing module, remove it.
 				// Since there are no other hooks for prop, remove the whole object.
 				delete jQuery.cssHooks[ prop ];
 				return;
 			}
 
 			jQuery.cssHooks[ prop ].get = function ( elem, computed ) {
-				if ( !support.pixelPosition() && jQuery.fn.position ) {
 				if ( computed ) {
 					computed = curCSS( elem, prop );
 					// if curCSS returns percentage, fallback to offset
@@ -605,7 +604,6 @@ jQuery.each( [ "top", "left" ], function( i, prop ) {
 						jQuery( elem ).position()[ prop ] + "px" :
 						computed;
 				}
-				}
 			};
 
 			return jQuery.cssHooks[ prop ].get( elem, computed );