Homemade teriyaki is soy, mirin, sake and sugar reduced down, and it takes about eight minutes — which makes the bottled stuff hard to justify once you've done it. Chef Ram was clear about glazing in the last few minutes rather than at the start, because the sugar burns long before the chicken is cooked. That's the mistake I'd have made. The pineapple caramelises properly if you leave it alone on the griddle.
Miles