I gave my bike a good cleaning the other day. While I was scrubbing the chainrings, I noticed something odd on the larger one. There is one tooth that is shorter than all the other teeth by maybe about 2 mm. All the other teeth look uniform and they all show similar not-too-bad wear. But I don't get why the one tooth is shorter. I'm not sure if it was always that way and I just hadn't noticed it, or if this is a recent development. Is this an abnormal wear pattern and is it something I should be concerned with?