A low battery was the culprit for me once. Never had the lights on issue, but the IR led would not pulse. I trouble shooted the DBC for hours, but int the end it was a low battery.

I did get one chip one time that seemed faulty. I was having issues with one of my boards. I swapped out the IC and the troublesome board worked fine. Have you got another board that functions fine? If you do try putting the suspected faulty chip in the functioning board and see if it behaves the same. If it does then you have found the problem. It is not out of the question that the PIC has a programing glitch in it.