“Lying” is an intentional falsehood. It’s not the same as being proven wrong. Bush did not admit to lying so far as I know, yet that is what Trump (& the Dems) accuse him of.
Trump seems to have problems with basic definitions. And I find that worrisome should he become president.
I don’t think Bush necessarily “lied” in his own mind. But he certainly was looking for any excuse to go after the guy who tried to kill his father.