Google AI Overview cannot be trusted at all. They will take a sample size of 1 (!!!) and present it in the AI overview.
How I found out: I made a comment on reddit on a very niche topic for which no google hit or and thus no AI overview existed. To my surprise the next day when searching for my own reddit post, google would happily copy my reddit reply almost verbatim into the AI "overview" box, linking no other post but mine. And my reply was also the only google hit.