Chris,
This is one possibility. Open up the access panel in the front to the headlight motor that won't go up. See if the wiring is all twisted around the motor drive.
A few months ago, I was at Papa Tony's to do the front bumper repair. Being the winner of his coveted "All Thumbs Award", he wanted to look at my electrical work for the BWM and headlight relay mod. When he asked me to turn on the headlights, one wouldn't go up, even though it was fine previously like yours.
We laughed when we saw the original wiring all twisted. First times for everything. Once we got the wiring untwisted and re-secured, it's been fine since.
Mike