So we probably should be careful with "translations" like this?
Not necessarily, but it pays to be cautious. Especially when someone is using only the English and is not comparing those to the original.
There are methods of translation called dynamic and formal equivalence:
The dynamic tries to convey the sense or meaning, the formal tries to be more word for word. Both are valid, but it's always better to translate from the original and to consciously decide which method you're going to use.
One thing I find annoying about Bailey is that he says outright "I do not understand the meaning of λεπτότης here." So instead trying to understand, he just decides it's the *wrong* word and fits in one he understands that's similar spelling.