Lets walk through it:
This is not a magneto, it’s works more like the old Ford EDIS coil pack from the 1990’s.
It works on the principle of “wasted spark”, so it also throws a spark into the the exhaust side.
That’s not a problem since there is normally no air/fuel available when that happens.
It also takes ~3 revolutions from the time this unit is energized until it actually start to fire.
My normal mag check is the sequence: at 1800 rpm switch from Both to Left only, then to Right Only, and then back through Left only back over to Both. I get a “BANG” every time since there are at least 3 revolutions of raw air/fuel mixture in the exhaust side when coming off the Right only position back through Left Only on the way back over to Both.
Only work-around I have is to throttle down after going to Right only to minimize the fuel/air in teh exhaust side when trying to get it back over to Both. An no, I’n not going to drill holes for 2 toggle switches to replace my stock rotary mag switch.