I have this recipe in a low-cal cookbook for maple kettle corn, and today I decided to try it. Except I didn't have the maple sugar the recipe called for. I did have maple syrup and white sugar, so I used a combination of the two. I don't think this is the only reason for my kettle corn failure, but I think it's a big one.
The biggest reason I think my kettle corn didn't turn out is that I didn't heat the oil before throwing in the corn kernels and sugary stuff, which meant it all blended into a caramel far too soon. The second reason is that I used a liquid sugar which, again, formed a premature caramel. This caramel trapped the corn kernels, keeping most of them from popping. The kernels that did pop were trapped within the unpopped kernels, and by the time a few handfuls have popped, the caramel was burned.
So there was that.
But that's how you learn, right? You make a mistake, you learn from it. Next time I try kettle corn, I will not make these mistakes.