I’m came here looking for a solution to erratic outro-fills. I found with the cue fill period set to next bar, sometimes the outro would play correctly and sometimes not, even though I had the footswitch set to play the outro and hit it on the same beat of the bar each time.
Through trial and error I noticed something. When a song is initial selected a ‘loading’ bar appears on the line of the display that says ‘Drum set’. I had been starting the song with the main pedal when this bar loaded and disappeared. This is a mistake. One has to wait for the name of the drum set to appear before starting the song, which, if the outro has some large custom samples could take several seconds. Waiting to see the name of the drum set solved before starting the song solved my issue and I hope this helps someone else.