For me it looks like it works as must be, the stricker always must have 2 clicks .
Maybe your striker on the door post is adjusted wrong and when you close the door it gives 1 click the door lock cannot came into the lock position.
when the upper mounting screw from the lock mechanism is to long , it also not will work .
Not needed to take the window out , only one bolt on the lower of the slider inside the door and a screw just above the door lock mec. on the outside of the door and you can take out the slider .
Sometimes the slider rubber is glued , but take out only the steel slider part.
Window must be into the closed position.