One thing worth trying on the door sensors, try bending the metal part that touches the bottom of the battery a bit so it makes better contact. This has apparently solved the low battery problem for someone the emailed our support team.
I'm surprised so many dead batteries have shipped, but I've confirmed that the date on the batteries is the production date.
We can get the sensors replaced if it comes to it, but it'll be done by our sensor partner and I have yet to have a confirmation from as to how we should proceed in doing it.