Must be the cook. I make my own mayo (and sometimes ketchup). My mayo comes out good but if you use cider vinegar...its weird. The type of vinegar you use makes a big difference. I try to use an oil containing as little flavor as possible. I love olive oil but not in everything.
Hubby eats Kraft mayo from olive oil. He thinks it’s healthier and maybe it is. I’m not a Mayo fan to begin with, but the olive oil mayo has something funky about it.