In the last but one f/w release there was an issue with the Optical handling. That was fixed in the last release IIRC. However, is it possible that there is still an issue in there ? Of course - yes.

I suggest that those with the issue clearly record what the issue is and when it occurs and send it into the HQ together with their config file. FWIW I am not getting any issues like this so it may be environmental (in the hifi sense) i.e. only with certain configs.

Rgds,
Nick