First thing to check, remove the mounting screws, that hold the dishwasher in the cabinet.
I would check and make sure the dishwasher is level in both directions, and the door and tub are aligned, and the dishwasher is as far up in the opening, without "binding" anything. then re attach the screws holding the unit, and recheck for a leak.

I would not think you have a "split spray arm seam", but it is a possibility, you may want to check it.

Is it possible, someone tripped on the door, or used it as a step to reach something up high ?

You may want to dismantle the door and check for damaged/bent door hinges and pins.

Based on your description, I think that's where you should start.

Good Luck,
:) :) :)