Building an app using sfplay~ and timestretching

I created this simple patch (see attached screenshot) to play back audio with three tracks (2 for stereo and one for click track). I then made it into an app to give a student to practice with. Everything worked fine, but then she wanted to changed the playback speed. No problem, I used time stretching and changed the playback speed of sfplay~. The patch works perfectly in Max. HOWEVER, when I turn it into a stand-alone app it no longer plays the click track (track three). I've tried many things and the only thing that will allow the exported app to play back track three is if I eliminate the timestretch attribute. But that's no good for what is needed (!).

Is this a bug in Max, or is there some special incantation I need to recite before exporting my patch as an app, or... ?!