It's not

Diabetes induced Peripheral Neuropathy always starts further away - toes/feet before moving up the leg. It is a vascular disease that kills the nerves starting with those furthest away fed by the smallest blood vessels

So best to get your issue checked out. It could be neurological or it could be muscular or even some kind of infection, but an isolated spot above the knee is "extremely unlikely" to be caused by Diabetes

Good to hear that because I'm having the same problem on my left above the knee