SOLUTION!!! I put up with this for years with my 2001 Lincoln Navigator.

The hardest part to fixing it is removing the interior door panel, so make sure you find out how to do that on your model before you destroy some expensive plastic parts. Once that is off, the rest is a piece of cake.

The problem is caused by the interior door handle rod. It needs to be adjusted because it is too short, allowing the door handle to open too far. A plastic clip attaches the door handle to the rod (the rod that connects the interior door handle to the door latch). Unhook the the clip and lengthen the rod by moving it back towards the latch, then close the clip to reattach the rod. The door handle will not pull open quite as far. Test the adjustment by switching the child lock to the unlock position, and while leaving the door open, pull the interior door handle open and closed rapidly several times. If the child lock switch no longer "climbs" from the unlocked to the locked position, shut the door and make sure it will still open when you pull the interior door handle. If so, you fixed it! If not readjust the rod and try again. Good luck.