I can confirm that after a playback stop and then a playback start the optical out will revert to OFF.
It goes like this:
After switching on the player the optical out LED is ON (without resume)
After playback start the LED is OFF
I set the optical out to ON, so now the LED is ON again
After playback stop the LED remains ON
And after playback start the LED is OFF
LED ON/OFF means optical out is working/not working
H140, build 20061108