GPIO Burnout Problem on Beaglebone Black

I’m working on a project and we keep seeing this bizarre issue where GPIO pins just stop working.

We’ve hooked up pin 25 (GPIO 117) to the receive side of a 3.3v RS485 transceiver to monitor for traffic on the bus. The pin seems to work for a little bit, and then stop working forever.

To add another level of bizarreness, this problem does not happen on the older beaglebone whites we have, only the blacks.

Any ideas? We can’t find anything wrong with how we’ve hooked it up or the signals coming in/out of the board.

Are you doing this part correctly?

http://www.elinux.org/Beagleboard:BeagleBoneBlack#Expansion_Header_Usage

Gerald