Interesting. If I set the master length to 64 (same as OT pattern), it works fine. Of course, my polyrhythms reset… But it’s a clue.
OP and others here with the same issue. Did you find a solution for this delay issue?
As for setting it up, this walkthrough is pretty nice: Launching A4 Patterns With Ableton Live/Push
It got my systems running. However, im still having the problem with 1 bar delay.
Maybe you have to set Quantization mode of the Ableton midi clip to the shortest value? I usually set it to 1/16 and my A4 receives message almost immediately. Then it plays its current pattern to the end and changes it to the new one. Try it in this way.