As you close the doors get down to a body line height so you can look straight on it. Gently let the door hit without pushing it shut and then while gently pushing look at the body line to see if the door is moving up or down as you force it into place shut. It is very often that the door is misaligned and the striker pulls it into place. So you can shut the doors and they look aligned, well yes, because they have been forced to be so. But the door should swing on it's own right into the striker and the latch latch without any movement up or down of the door.
How about on the step, has the rocker been hit from the underside pushing up the rocker a little? You may not have noticed that and it only takes a little sometimes. How about in the threshold of the door, is the trim on the bottom original? Has some accessory step or trim been installed that may be thicker and pushing up on the door trim? Or is that trim out of place, has it been pushed around and the clips aren't going into the holes properly or something like that?