I think it should be ruled a NC. They overturned Rahman's loss to Toney on the same grounds.

I feel sorry for Bradley though, he was dominating the fight and Campbell was clearly using it as a way out screaming that he couldn't see etc.

But it was a headbutt, and as such a N/C is fair as it was stopped inside 4 rounds.

I expect Miles is simmering with rage over the whole episode of course.