Hi.
FWIW..... Gottlieb 2001 with two coin chutes has the same behavior on the left/1st chute.
Inserting a quarter in the left/1st chute decrements the credit wheel by 1 and immediately starts a game (and there is not a 1st chute setting jumper of which I am aware/which I can find).
Inserting a quarter in the right/2nd chute (with the 2nd chute mech panel jumper set to 2 plays per coin) adds 2 credits to the wheel and the start button must be pressed to start a game.