Our ION console begins to scroll through the cue list backwards until it reached the first cue of the show intermittently when the inhibited submaster for the fog machine is lowered. The live cue is not affected when this happens but no cues can go until the submaster is raised. This has occurred on two occasions during the run of the show during Act I. The board is restarted at intermission the issue does not occur again. What could be causing this issue?