Yup, I've had that on KO Gen 3 carts before -- I can tell you right now it's not supposed to happen. The music also subtly changes a bit after, right? Just enough to be weird?So I recently found a copy of LeafGreen at a thrift store. Maybe I'll get used to it, but the fact that the music cuts out halfway through saving keeps making me think something is about to go horribly wrong.
Still, I've had these problems and the carts have otherwise worked just fine. You can even trade and transfer so you're good to keep going with it, just know it's not legit.