By "cap was not on correctly", I'll of course re-assert that there may have been an inability for my specific cap to seat itself correctly. That would seem to be the $199 question
On a technical note, in your experience could a loose-cap reverse the polarity of two 1/4" rare-earth canopy magnets that are 20" from the spark plug ?!
In the case of the extra 300 that is exactly what happened when the engine was fired up. Rare earth canopy magents do not come loose for dear life, and the rear canopy popped
up and "hovered" with the engine on ... and reconnected with the engine off. (The canopy would have popped off, but there were two dowels securing to the fuse on the other end.)
In hindsight, that should have been a warning sign - but nobody at the field had ever seen it before and at the time the consensus was that "vibration" was shaking the canopy off,
since the engine was vibrating more than your usual nitro (not a knock, gassers just vibrate more).