Same here, still it works fine on city sample. I looked evrywhere but couldn’t figure out why.
I found a workaround:
I created a 5 second wav file with no audio that I set in loop.
First, I play the dumb wav file and while it keeps playing I can play the “play tone match” in the motosynth source or the “start engine preview” in the motosynth preset.
But when I play the project in the viewport, everything works fine.