I've had it go into safety (fault mode, if you will - where the light turns orange) before. I can only recall two instances though. One was when my laptop ran out of batteries and the ODAC powered through USB got forcefully shut off. Luckily I didn't have my headphones attached at the time. The other instance was during a meet, when someone had accidentally turned it on at 4'o clock. Luckily, my headphones were still fine.
I'd check to see if the ODAC is having problems as that's what caused the orange lights last time.
Interesting, I'll plug the Mini-x into my D100 instead and see if it still has issues.