Ableton Forum

So basically, I've been able to fix it by routing the sylenth tracks to an empty audio track, playing it back, once it starts playing automation turns off, so start the playback again without pressing stop, it'll stay on the second time, then record in the empty track. Long process if you've used ...

So it's a confirmed bug with Ableton/Sylenth1 :(

From Ableton Support:
I was able to reproduce the same problem here with the latest version of Sylenth, so it is indeed a strange issue. The problem has cropped up before, very seldomly, and I regret to say that it has yet to be addressed.

To ...

Yeah, very weird. I think it has something to do with Sylenth1, have also seen people having similar problems with Massive.

Have tried freezing and locking envelopes as well, nothing works.

Just upgraded to 9.1.2 and it's still happening. Frustrating. Am reporting it as a bug but hoping to find a work around tonight, have a project due tomorrow and no automation is going to really kill it.

I'm having this exact same issue with a track. Everytime I export the automation turns off automatically. Also happens when I playback in arrangement view. Keep having to re-enable anytime I press play or export. So strange. Never had this issue on any other tracks. Using Ableton 9.06 and Sylenth1.