Wow, just went through my msg history... of empty leg flights I've booked, I'm 2 of 6 in Q4. Fully 66% have been cancelled by the operator.
Two for maintenance, and two for schedule changes (e.g. 'Your reservation was not confirmed.') Only two actually flew.
I really hope it gets better In Q1 next year. The amount of effort that goes into planning for an empty leg (hotels, car, flight home, etc.) isn't worth it w/o better reliability.