Door Stuck On Opening

It seems the strike is installed too far toward the inside of the car. When the door is closed is it smooth with the quarter panel when the latch won't make that second catch? I had that issue on my most recent Dart reassembly. When the strike and captured nut (inside the door post) is loose it should move around, limited by the hole the strike goes through (or by the loose captured nut if it is rusted, or inadvertently welded in a fixed position). I had to take the strike out and make the hole a bit bigger toward the outside of the car to get the strike in just the right position. This situation is more critical if the strike is either high or low in the hole, as the in and out adjustment is more restricted there. I also had to repair the area of the door post around the strike and I think that was what had the hole in not exactly the perfect place.

In reading the old thread above there was also something about the latch "popping the door open" That is not correct - it is the compression of the door seal that does that. The OP didn't have the door seal in place so, of course, no "pop".