There's a few possible explanations, as I think Exophase will take some time to get all the data from the Sony.
As far as I can tell there are issues on Sony's side where the app fails to update properly, it where they seem to delay the number of hours on their end. But I'm seeing 1 hour 11 minutes for your Fortnite time. (With Uncharted triple pack, this it more or less sticks all playtime in Uncharted 1.)