First at all, sorry for my bad english, I’ll try to be the more specific as possible.
I have a facebook game made with Unity and using Facebook SDK for Unity, that was released to facebook canvas first. After of this, I made the mobile versions for Android and iOS, so I added at Facebook settings, enabled the “Single Sign On” and “Deep Linking” options for both platforms.
And my FB.Feed configuration on code looks like this:
FB.Feed("",
"https://apps.facebook.com/epidemia-electoral",
"Superen mi record de " + ParseUser.CurrentUser["score"].ToString() + " votos en Epidemia Electoral",
"Epidemia Electoral de SDPnoticias desarrollado por Mixtli",
"En Epidemia Electoral debes evitar que los enemigos de la democracia ejerzan votos malos",
"http://static.sdpnoticias.com/epidemia-electoral/principal.jpg",
"",
"",
",
"",
null,
DespuesDeCompartirCallback);
When someone shares their score on their Facebook wall through the game, and this publication is viewed from the native Facebook application on both Android and iOS, the link is directed to the one specified in the configuration of FB.Feed (ie, the canvas) and opens in the facebook’s in-app browser, instead of launching the application.
I have understood that setting the Deep Linking as you can see above, should suffice for Facebook to launch the application.
I understand that this error occurs in the native facebook application on iOS, as the game is not yet in the AppStore, but still in the Android happens and my game is available in Play Store.
I appreciate the help you can give me, I’m really stuck with this and do not know what to do.

figuring this out was a pain in the ass for me too
– taxviThank you taxvi, it was just what I did and I solved much of the problem, except that instead of opening my Android application always asks me if I want to install, even if it is already installed on the device.
– boggartok in this case there may be one of the 2 things going here: 1. you did not provide the correct deeplink to the facebook tool. your deeplink should be fb12345:// and 12345 being your facebook app id. 2. now if the first step was done correctly than you are not providing the deeplink in your plist file on iOS (I don't know about Android). read the configure plist section of facebook sdk integration for iOS >> https://developers.facebook.com/docs/ios/getting-started#configurePlist
– taxvi