I'm assuming the high note you're referring to was a bend. If so, I had the exact same problem with an old Ibanez RG270. After giving the neck a little relief with a minor truss rod adjustment, the problem went away. Either that, or raise the action so high, even a slow Blues player would cringe

mg:
Maybe try finding another guitar of the exact same model. Sounds like a flaw on that particular guitar you were testing.