The same thing happens with a lot of fruit honestly. People cut into a mango and eat the part right around the pit, which is stringy and sour, then toss the cheek pieces that are actually sweet. Or they get a whole watermelon and dig straight into the middle when the best bites are closer to the rind. The trick your coworker showed you works because the flesh near the skin gets more sun and more sugar while the middle stays watery, and once you know that you can't unsee it. Dragon fruit specifically is also way better when it's actually ripe, if it's firm and greenish on the outside you're already fighting a losing battle no matter how you cut it. So now you gotta go back and try yellow dragon fruit too, that one is sweet all the way through and makes the red kind taste like nothing.

Wait, the flaps actually made the gauge drop? That is wild. I would have bet money it was the sender too, no question. Eleven hours on a chafed wire behind the panel sounds about right for this kind of work, those gremlins love hiding where you least expect them. What gets me is how a flap motor pulling current was enough to kill the gauge reading, that is such a tiny load change. You are not a rookie for missing that on the first pass, I have seen guys with 30 years in the shop chase stuff like this for days. Honestly the fact that you found it at all says more than how long it took.