Hummm..., that does seem a bit odd. I remember some older cars you had to push the lock down on the inside and then hold the lever up or push the button in (depending on the design) to make sure the door locked as it was being closed. Otherwise even though the lock was down inside it would auto unlock when the door closed. Maybe something got reversed???

I wish I could offer some insight into WHAT is wrong, but I can't.  What I CAN tell you is that something isn't right; the Ford Pinto/Mercury Bobcat never had self-locking doors as a feature!  Good luck with figuring out the problem.

Dwayne

It sounds as though the "Spring Tensioner"(I'm not sure of it's actual name), that holds the Door Locking mech either in the unlocked or locked positions may be worn/broken/missing. So that when shutting the doors, the door locks fall into the lock position as though 'Automatically' I don't know for sure, it would be odd for all doors to do this in the same vehicle if it wasn't made to do on purpose.

Michael

Sure it's not a Gremlin ? 

Any pictures of the car's engine bay yet ?

It’s just weird that both sides do it. I’ll take some pics and see if I can post them.