Like the title says, if Kirby is hit during his horizontal air cutter, he loses any jumps available to him. Not sure if this is an intended feature, but seeing as he keeps the jumps if he's not hit, seems like a disconnect.
As a side note, he also loses jumps on the vertical version, but this one is understandable.
As a side note, he also loses jumps on the vertical version, but this one is understandable.