I have been poking around on this one today. At first I rejected blocking the Mist sense beam as the reason, because it showed not to be a problem. That is, when blocking it before draining balls. However, it can trip the logic on a specific seqence of events.
The hazard is as follows.
During Mist MB, either solo or stacked, when draining down to one ball-in-play. And after all balls in the trough have settled on their trough switch, and before the feed a ball to the Mist pocket procedure has started, there is a small window where blocking the Mist beam will trip the game to go to end-of-ball.
From my investigation, the “switch closure” of the beam do not have to be of any substantial duration. So shooting a ball pass it might do the trick. But it will have to be done with the right timing within the sequence of events.
Having balls in the Castle lock trough does not change how this works.
There is an additional hazard on the game regarding the Trough 4 switch. Which can kill the current ball-in-play at any time. But only when closed for a couple of seconds. If bad switch, dent trough or bug-in-the-matrix, yes. Otherwise I lean towards the Mist beam theory.
