Ashley Pomeroy: I have the 14mm - as a cinema lens the biggest problem is the odd and very noticeable distortion, which is barrel-y in the middle and pincushion-y around the edges. Makes it odd for filming unless you don't mind the quasi-fisheye effect. I wonder if they fixed that?
There is actually a name for what you describe: It is called "mustache distortion". It is not common, but neither is it rare.