Sorry for the delay. Can you check not just the user's front-end timeline profile view, but also the "Activity Log" on Facebook? You can get there by clicking the Activity Log button in the bottom right of the cover photo area. In there, there should be a listing of all activity that any app has submitted for the user.
If it shows up there, that means it was posted properly. From there, Facebook decides what's relevant to the current viewer and whether it should display on the Timeline, ticker, friend's news feeds, etc. On the Activity Log, you can also hit the white-circle on the right and choose to force the action on your timeline or never show it there.
Hope that helps explain. If you're not seeing it in the Activity Log area, let us know as that indicates other types of issues.
Thanks,
Alex