Wanted to share this just incase anyone had had a similar issue.
I have a boron gatewaying for 7 xenons and its been working fine for many weeks. It has been connected to mains power with a battery attached. Battery is the 1850mAh one supplied by Particle
I had the boron sleep through the night to conserve data trans.
Yesterday I switched it on and it went imediately into deep sleep. I checked code, reflashed several times all to no avail. It was unuseable.
Then i noticed that when i plugged in a usb cable the battery charge light went bonkers. So i swapped the battery over and it returned to perfect operation.
This does however raise a question. Can a boron be run on mains power with a battery fitted for a long period of time?
Im thinking of putting the charger on a plug in timer so as to give the battery time to discharge.