I need one of those German words

[lokifan]

Does anyone know if there's a specific term for the moment when someone who would otherwise be a trusted source on something they know much more about than you do, confidently says something that you know for a fact isn't true? And the way it makes everything else they say, about things where you wouldn't know if it's true or not, less credible?

It'

Comments

[ceciliaj]

dyyyying for the context

[khalulu]

When I was in elementary school I confidently told another kid that Mary Queen of Scots and Marie Antoinette were the same person. (They were queens a long time ago, they got executed, it seemed clear.) He looked dubious but didn't challenge me because I was the smart kid. But perhaps he regarded me with skepticism ever afterwards.