Turns out the electric igniter was closer to the outer corner of the gas tube than it was to the proper grounding electrode. So the arc would go from the igniter to the outside corner of the tube, instead of between the tips of the electrodes – in front of the tube.
So the spark wasn’t in the gas flow. So it wouldn’t start on the first try. Then on the second it would “whoomp!” mini-boom. I got it down that the first try I wouldn’t let timeout… just let it try for a couple seconds so not enough gas to make the mini-boom would come out… just a little. Then try again, and it would light and work fine.
So on the first try, there’s no gas around, and it’s not in the stream, so it doesn’t light. Second try, there’s enough excess gas floating around that it’s able to light from the spark on the outside corner of the tube exit.
I tried SO MANY things over the years. Finally figured it out today!
I like when we finally figure out what’s wrong, and dislike sometimes it takes so long. Great for you and is something to remember for me.