Door AJAR light/prompt won't go away, then when I lock w/ remote it double beeps

It double beeps because it thinks there is a door open. You probably have a bad door switch or wiring problem to switch. Also be sure all the doors are shut before thinking there might be a mechanical problem.

You will want to make sure that the hatch door / glass door is closed, it may appear closed, but if you accidentally hit the button instead of your door button, the latch will open, therefore causing a double beep. Hope this helps.