Oh wow... at least you can still unlock & and get in using the key. If you get in a situation where you have to get in the wrong way, you can turn off the alarm by turning the ignition key on-off-on.
Hmmm - long shot... any chance that water isn't draining out of the door (clogged weep holes)? The electric lock mechanism is the lowest item within the door and very close to the bottom.