When using a Popup Action for “OnTouchEnd”, if you have modal and background dismissible selected the screen will not stay open. You see a brief flicker, but then it disappears. If you make the action a script and open the popup using scripting everything works fine. Additionally, if you use the Popup action and select only background dismissible the popup opens, but in my case opens behind the popup that had the button to launch the new popup. When using scripting, it opens normally.
Bottom line - the Popup Action does not behave the same as popups fired from a scripting action and the Popup action is the one with issues.