Smoked turkey legs..did I do something wrong?

Smoked for 2 hours and they turned black. 135° at that point, finishing in the oven at 350 until done because I'm worried it'll get worse.

Vertical propane smoker, began on lowest setting and turned it up to medium low over the 2 hours. I only have the thermometer on the front of the smoker so no accurate temps. I used a few apple chunks and more apple chips. I used Kingsford smokehouse classic seasoning.