First thing to do is to remove the striker plate completely and see how the door feels pushed shut. It should have no binding and not be hard to fully close. If it does have trouble, you need to re-adjust your hinges to let the door sit away from the rubber a bit.
If it seems good, then the problem is in the striker adjustment itself. One thing I learned, a little goes a long way! Move slightly, test, move slightly re-test, keep going until it works good.
One other thing, the striker also has shims so not only can you adjust it in, out, up and down but also closer or further away from the cab jam. Lots of possibilities and that's why it's good to rule out the hinges by doing the above.
