I’ve been working on a project at the tempo of 174bpm and have noticed on my neighbouring midi-synced machine (Octatrack) the tempo drifts up and down from 173.9 to 174.1 and never stays put.
This creates some stuttery artifacts on some timestretched samples which are undesirable.
I figured it may have something to do with instability at higher bpm’s so I halved it to 87 and voila! Perfect sync, no drift at all.
For all those suffering with some midi tempo instability - halving the tempo (and setting x2 pattern length multiplier) may work for you, give it a shot.