[Neus]

You use the Cherry Pie.
You eat the Cherry Pie. Your hunger has been satisfied for 13 battles! You also feel more motivated, gaining 30 bonus Experience Points.
You use the Cherry Pie.
You eat the Cherry Pie. Your hunger has been satisfied for 14 battles! You also feel more motivated, gaining 30 bonus Experience Points

Sadly I can't replicate this. You can try unequipping and re-equipping the stamp and seeing if that helps, maybe?