just trialed this out, burnt a 79minute audio cd in nero 126.96.36.199
The entire burn process was ORANGE on the led, burning data cd's is always red.
I have a very capable system so buffer underon is nowhere near close and the burn process took the usual 2 minutes 30 something seconds
I did some research and found this on Liteons FAQ page
Orange LED light (when green and red lights lit together) indicates Buffer UnderRun protection function enabled.
So this is Buffer underrun protection kicking in to protect against underrun regardles sof buffer size and from what ive tried it ONLY kicks in regardless of buffer size in audio cd burning mode, the mode that would need the best quality burn.
This I see as fair enough and the drive is functioning normally so nothing to be worried about