John... were you by chance in the vapon.tv channel last night? LOL, there was a John there with the same issue.
My husband had the same problem with cinnamon. It was the flavor that ultimately got him to totally quit regular cigarettes, but he melted a tank. I tried it in a metal tank but had a really pretty plastic drip tip on it. Big mistake, it turned it into a goopy, sticky mess!
Cinnamon hurts my chest anyway, so I steer clear of it!