Well, I verified that the syrup has sugar in it.
Brew day got delayed several weeks due to some cold/flu issues going around the house and general lack of free time, but I pitched 12 oz. into my pecan porter at high krausen a couple days ago and the yeasties went crazy on it. While I slept, new krausen filled the last 5+ inches of headspace and pushed into and all the way out the airlock. When I came down in the morning, the airlock was plugged and the bucket lid was bulging considerably. Luckily, I caught it before things got really bad.
The taste was different than what I was expecting. I thought it would taste like Grade A on crack, sort of like a "hit you in the face with maple" flavor. Instead it was a richer, fuller flavor if that makes any sense. Sort of like what you'd expect when you reduce a sauce when cooking. I'm excited to see how much the flavor comes through in the finished product.