Confessional Misspeaks

Has anyone else ever noticed how many Survivor (and Big Brother) contestants mess up common American phrases?

For example, instead of saying "I'm on top of the world," or "I'm over the moon," the player would say "I'm on top of the moon."

I swear it happens once per show, probably more, especially on BB.

I feel like the producers must be coaching them so say phrases they normally wouldn't, then in the moment they flub their lines.

Anybody have thoughts?