Mine latches/clicks twice. the first latch is a safety latch,that holds the door to the body of the car preventing it swinging open during a corner/turn if not fully latched(and yeah a kid CAN fall out of the car,I saw it happen to my next door neighbor in his 64 falcon). the second latching or click locks the door in closed position. you can pull the door open about 1/2 inch or more if your only on the first latch/click (mis-adjusted or or you have a bad 1st gear tooth on the door jamb side messed up)
there should be little play on the gear but it will rotate only one way easily that's the gear that moves the back side star latch mechanism. View attachment DSCF4864.jpg