If you follow the link to the source site (Tatoeba) you can see other translations.
https://tatoeba.org/en/sentences/show/143223
As good a time as any to remember that anyone with any level of ability (or seriousness) can contribute to Tatoeba. And Jisho just grabs sentences automatically.
Also worth noting that it's not necessarily the case that sentences on Tatoeba were originally Japanese and then translated to English. They might have gone the other way. Or they might both just be translations of another language.
To be "full of beans" is an English expression that means to be healthy or full of energy.
There is nothing wrong with the translation.
@Fredora does it actually get used that way, like this with the negative? Googling for "not full of beans" mainly returns results related to this specific sentence and not other stuff.
As an American the original sentence sounds ridiculous anyway, so I'm genuinely not sure if the negative version is natural.
@Leebo "full of beans" is familiar to me as a New Zealander, but it sounds a little unnatural in this phrase, mainly because "full of beans" is more colloquial, and so doesn't fit the tone of the phrase. I would use "lethargic", or "who is not energetic", or something like that. I personally haven't really ever used "full of beans" in a negative sentence, but I am far from being an authority on the English language! By the way, thanks for all of your forum contributions, I am picking up some interesting points about Japanese!
@Kiwi_des_neiges thanks for the info!
Beans???
This translation is hilarious but I don't believe there's any mention of beans in the Japanese.