Mixdown Errors, when mixing down a song

Hello,
I’m experiencing some problems during mixdown. Is anyone else?
It seems the MIDI tracks (drums and bass usually) are not keeping time with the audio tracks when mixing down.
They play perfectly well during normal playback but after creating a mixdown they become out of time. This is also quite random as I’ve tried several times to mix down a song and had different wrong results each time.
I have been using N-track for years on the same windows laptop and usually had great results but now I can’t figure out where I may be going wrong.
Has anyone else experienced this who may be able to help?
Many thanks, Ade

Ade,

the issue was in 9.1.8 Beta and the latest beta released last friday (build 6673) contains the fix. Please let me know if you still see the issue in the latest build.

Flavio.