To be fair, it may be that the optical output appearing early is deliberate; designed to interface with amplifiers which accept it directly, and take a little time to effect the conversion.
The toslink data format is quite complicated and inevitably involves a delay before the digital to analogue conversion that follows its decoding.
My remarks apply only to conventional amplifiers which accept an electrical signal and produce an electrical output to speakers with negligible delay.
I was pleasantly surprised at how little the optical to analogue converter box cost, but horrified at the cost of the lip-sync converter. Of the two, I would have thought the lip-sync unit the simpler of the two in terms of its function and the amount of hardware involved.
But if you are looking at getting a smart telly, be clear about what you wish to connect it to, and make sure it is compatible.
On a related matter, I have a number of radio controlled clocks - and a radio controlled wrist watch which are spot on of course, and am amused to hear from TV and DAB radio if both are on and in hearing distance, a series of variously delayed repeats of the pips or Big Ben coming a second or two later than they should.
I guess its progress, but it sounds chaotic to me!