I'm confused. You said you found a bug in the hash? Or are you considering the lack of verification to be a bug? I left it out kinda intentionally since submitting "bad" solutions doesn't really hurt and I just didn't bother with the CPU verification. But yea it would be nice and very helpful in debugging. Running in benchmark mode with a low target would be a good tool for checking if the GPU hashing works or not, instead of having to wait until you actually solve a block.
It is a bug in my version. I have replaced some of the kernals in the miner to give a small boost. When changing kernals, things can go wrong, and it would be helpful to have the cpu to doublecheck the result.