Show Cue System

I've noticed that every so-often a video cue with an assigned fade-in time doesn't fade in - it just stays black until the end of the assigned fade time, then it snaps on.

I can't reproduce this at will, and I can't figure out what factors might be causing this behavior - it just seems to happen once in a while, and when it has happened during setup or rehearsal I've tried going back and running the same cue again and it works fine. This problem isn't specific to recent versions, I've noticed it in earlier versions too.

I'm wondering if anyone else has seen the same thing or if anyone has any ideas what might I might do to try and prevent it.

Thanks,
Tim.

When the problem did occur, was it during a cross-fade from another currently-playing video?

I think I've seen it during cross-fades in the past, but when it happened this week it was a fade-in with no previous slide displayed.
It was a tech rehearsal so we had been skipping around and then went back to the beginning of the show, and it happened when the first backdrop was supposed to fade in.
I will try to pay attention to whether this ever happens during a straight run-through.