The attached shows a top-down pictorial of the scenario you have on the corner. The blue lines would be your outer profile, starting at the door jamb to the left, and working around to the rear of the cab. When the weld dots shrink along a length of weld like you show, it will also shrink the overall length unless the welds are planished. When the arc profile shrinks in length it makes a shorter arc, or in essence, pulls the metal into a valley. The side effect of gathering this metal tighter together is that puckers and oil cans will form. You get rid of these side effects by planishing the weld using hammer and dolly to add stretch back into the equation. When the weld stretches throughout the arc, it will bring the metal back out where it belongs and also release the tension that is forming the puckers and oil cans. When you reinstall your door I fear you will see a wide gap at the bottom adjacent to the vertical weld, where the shrinkage occurred. Planishing the weld stretches this area to push the edge of the door opening back where it belongs to restore a parallel gap. Welding without planishing the weld to counteract the shrinking effects is just an open invitation for all the issues you are having.. The process is discussed in the Mig welding tricks sticky thread.
