Kassen, I completely forgot about me.yield(), which makes me feel
pretty dumb. But I guess concurrency is not as simple as Chuck leads
me to believe!

Don't.

In fact I have a suspicion, looking at things like we are now, that I too missed it a few times in recent history. It's a specialist tool and kind of out of the way, syntactically.

I think I pointed out before (on the forum, I think) that while ChucK is deterministic in timing that doesn't need to inherently mean you or me will be able to easily predict timing in tricky cases like this. Especially the event cue here is a questionable bit, at the very least the priority (order of execution) between OSC messages and ChucKian events while yielding is underdocumented as far as I can tell.

I fear Ge will have to shed (shred?, seeing how he's quite bussy these days...) a light on this issue and IMHO it's clear that the OSC hyrarchy needs cleaning up as well.

I realise this is a urgent question to some and in that sense a bad thing, but I also feel it's very good that this issue which is very much at the core of ChucK's way of dealing with concurency and timing is brought to light in such a clear and practical way now. Similar scenarios have been naging me for a while now but never in such a practical and clear way.