That's what I was thinking. Maybe it's meant to be sweet potato plant? That or it was very little potato leaves which I doubt
Correct. The leaves in question are 'imo no ha', leaves of the sweet potato plant. Where I'm from, they're commonly translated as 'potato leaves', which I should've realised is a careless localisation that leads to misunderstandings for an international audience. (They're one of my favourite vegetables to eat, so I must've grown complacent after seeing their incorrect name all the time.)
Thanks for bringing it up! I'll edit the translation to be more clear and less poisonous.