It's because the game ID for Uncharted: The Lost Legacy is shared with UC4 on PSN's side. So it appears the hours played are getting merged into UC4. I think it is doing that on everyone's profile.
I'll see if we can fix it. I know for other games like this, it is not fixable - since they are only sold in a bundle and PSN only reports the total playtime for the bundle (Borderlands Collection for example). But UC4 and The Lost Legacy are sold separately, so it might be fixable, in this case.