Caustic Song file (optional):
One slew over the cuckoo clock.
If you open this file, you will see a Master Clock. It's self generating (as is, pretty much, everything else), and takes a few seconds to get going. Look for activity on the output meters. Once it's up, and running, the mixer input, marked with song automation, is the 'Rate' control. There are some long, random, crossfades, and a couple of machines are doing their own thing, but everything else is locked to this 'Clock'. Master Delay 'Time' is unsynced.
Master Volume is down. Check the master effects meters for any major spikes 'Before' you turn it up. Some of this takes a moment to settle down, and can sound, pretty, nasty until it does.
Don't sweep the 'Rate' control, from one extreme to the other, too fast, or all Hell will break loose (for a bit). Otherwise, it's, remarkably, stable.
Try feeding 'Velocity', from the other sequencer, into the Rate input.