Oh no. I've got a pumpkin wine and a flower mead perking, and spiced porter I just bottled, and I used cinnamon sticks in all three brews. I hope the effect you got was because of the fresh-ground aspect? I used sticks so I wouldn't have to triple-strain, but now I'm hoping it mitigated the spice effect (which was supposed to be subtle). Please post how the ale eventually turns out...

I don't know if this is applicable or not....

This is also second hand information and not first hand knowledge, so please take this with a grain/pinch/barrel of salt...

I've been warned about the use of cinnamon in brewing, as many "grocery store" varieties of cinnamon are actually something else heavily dosed with cassia oil. Most oils are bad for fermentation and brewing, so if you do use any cinnamon, make sure you are getting the real deal, and not the fake stuff dosed with flaboured oils... IIRC this is more of an issue with cinnamon sticks than with the powdered variety, but it could be both....

I used powdered cinnamon, the real stuff, for a pumplin ale. I didn't use much more than a couple of tablespoons for a 5-gal batch. I essentially spiced it to taste before the fermentation commenced. It came out with a very subtle cinnamon flavor. Remember, though, it had EKG and Cascade hops to contend with, also. If I can find my notes for that batch, I will let you know the exact amount used.

I used 6 cinnamon sticks in a 4 gallon batch of mead and it turned out fantastic, not overpowering at all.