Well, actually I am an owner of the LinkTheater - But as the Firmware base is the same...:
1) Does not occur at the same place, even if the movie is watched twice. Occurs on every DVD (e.g. Moulin Rouge (Had several hiccups...)), I have played so far - And yes, mostly in the second half of the movie.
2) FW 10.80 (Current beta - I guess it's possible to relate that to the Snazio...somehow)
3) Problem still persists, but usually different time / quantity ...
4) I never had any stutter, just the fast forward effect
Those Sigma based players really are great, but if this issue isn't fixed with the next release I'll probably give it back and wait for the next generation, as the main use for me IS watching DVDs
Edit: I should mention that all the DVDs have been watched with Dolby Digital/Surround sound...Dunno if it's important, but maybe it's an Audio buffering issue...