I think we've all made the mistake of getting too close to a grumpy bird and their house or claimed area and not noticing when they come up to correct us. I've been bit on the nose, arm, lip, ears, neck, etc. The ear bite didn't end well for lurch but I should have known having my hot cereal while he was out was a huge mistake. He spent a while in his cage birdy swearing at me and I was pretty mad for a while.
I finally let him out and he complained and gave me the look and finally in the early evening landed on my chair back and said Hi Sweetheart so we were OK after that. I never made that mistake again.
Nerd had a thing about toes and feet and bit my toes quite a few times when I forget and he didn't. It was equal though has he hated having his feet touched too.
Dobby has chosen my sister but luckily merely gets offended and gives me the look if I come up and try to interact. Biting is the last tool in his box but Momazon has verified he can bite, just usually chooses not to as they did such a great job socializing him.