Violin defaults to "slow" patch
1) In 3.1 Beta, create a score from the String Orchestra or String Quartet template.
2) Open Mixer.
3) Since it's 3.1 Beta, all sounds are replaced with their "Expr." (expressive) variants. However, with violin, the reassignment goes awry and uses the "Violin Slow Expr." instead of "Violin Expr." sound
4) Result: in playback, short notes of the violin are not fully heard because the beginning of every note starts slowly.
5) Workaround: manually reassign to "Violin Expr."
The same incorrect reassignment happens when opening an older score, but the templates are the easiest way to reproduce it.