For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.
Bad CPU, very likely.
Don't waste time with this board.
Do not risk to give warranty for any repair.
It will come back soon for other reason; then explain to client is no covered by warranty.