Beat sync broken in 6.8.4

Is anyone else having problems with Beat sync in 6.8.4? Tracks that worked fine in 6.8.3 are just not sync'ing in 6.8.4. Sometimes I'll start a second track and it just won't snap to the beat of the first.
Other times, the sync area on the screen will turn yellow and change to "bpm sync" on its own. But even if I switch it back to "beat sync" it still just seems to ignore the command and won't snap songs to a beat.

This only happens sporadically, and I haven't been able to find the pattern. For the affected songs I tried re-analyzing but that didn't seem to make a difference.

Pending a bug fix, can anyone find a link to get 6.8.3 again?   I can only find 6.8.2.