Occasionally the k key is not very responsive

I just received my new MBP today. I'm extremely happy with the system but there is one glitch. At times it takes more pressure than usual to register the letter k. It doesn't always require more pressure, but it is often enough to be frustrating. I've checked all of the other keys and they seem to be working fine.

Does anyone know of an easy fix for this or am I better off returning it for service? I do have a return box on the way, but I really don't want to have to use it.

Thanks in advance for your advice.