Super Pac-Man: Start 1P button acts as coin

[Thelypody]

With stock core settings, Start 1P button in Super Pac-Man acts simultaneously as both Start button and coin insert. In effect it causes the game to start immediately once the button is released. Pressing the Coin button on its own does nothing. If you hold down the Start 1P button, the game registers credit on button being pressed and stays on title screen as long as the button remains pressed.
You can also press the Coin button while holding Start 1P to instantly launch the game, which makes me think that currently Coin button acts as Start 1P, and the Start 1P button acts as both Start 1P and Coin.

[Thelypody]

While experimenting a bit, I've encountered an extra oddity. After resetting all settings, input included, pressing coin would trigger a sound effect and title screen update, but the credit counter would still say 0. Pressing the coin button the second time launches two player game.