If after refreshing the APP the Post Links for a particular product aren't showing;
There is a good chance the product exists on another Layout that doesn't have the POST LINKS added.
When an item is first added to a layout, this is what then sent to the app dashboard database.
Here is a view you can get in V2U which shows you the layouts a product is on; I went to Menu, found the product I was after and scrolled down to see it is on two layouts.
Then simply find the original layout with the product and duplicate the settings.
Refresh the APP, it should work.
Because of this it seems you can only have one set of post links if you have the product on multiple layouts.