Weird, I haven't experienced this..the value should get changed as soon as you drop the ball.
Are you able to send me a recording?
If there's a way to DM on Itch, I'm not finding it!
Here are screenshots instead. You can plainly see that when there are 2 balls left, the button says "ball", so clearly at a code-level, the game thinks there's only 1 left and then that's what happens, it drops only 1.
Also note that for some reason "Boring Guy" is up there in the top-left corner for some reason and it's there even when in other menus, like here:
I hope you find this helpful.