As of the 1.8.0 beta (this may have been present in 1.7.0, I'm not sure), I'm having issues with game data in the "Games" menu on device. Games display 0B of data even though their Data folder is not empty, and there is no option to delete data like there used to be (this definitely worked in 1.4.0). I use this feature often while testing game saving.
This is also happening for @pichuscute so I think this might just be a firmware issue. Happens for my sideloaded games as well as the season 1 games.