All iq tests contain some crystalized knowledge as well as pure reasoning.

I know there are questions my kids have missed for lack of exposure to content.

But that's a different issue from bad vibe from tester. My 2e child had been tested 3 times now, didn't mind the first tester, loved the second, hated the third and really regret using him.... And I think his having he personality of a plank did affect my DDs performance on the verbal..