feel passionate vs passionately about

I teach English in South Korea.

One text book says that only the following sentence is grammatically right: "Highly skilled athletes feel passionate about their successful involvement in sport"

But the next sentence is grammatically wrong: "Highly skilled athletes feel passionately about their successful involvement in sport"

I am bothered by the curiosity.. Could you explain why the latter sentence is wrong?

Here is the context.

Values are defined a a person's beliefs about what they consider important in life. For example, an athlete who values commitment, responsibility and health will tend to develop daily rituals and long-term habits that promote their high-quality sports performance and good health. Highly skilled athletes -and their coaches- feel passionate about their successful involvement in sport.

This is one of those contexts where usage has changed over time. This was the situation until just a few decades ago...

...and this is the situation today...

I would just say that if anyone thinks people have started using a different form of words because they're conveying a different meaning (no matter how "subtle" the difference might be), all I can say is I think that's a nonsensical position.

To the extent there's an "explanation" for this relatively marked usage shift, I'd say it's just that Anglophones in general tend to prefer simpler forms when they're not being intimidated by grammarians telling them that a context like this requires an explicitly adverbial inflexion on the relevant term. Which it obviously doesn't.

If you follow either of my links and switch to the British corpus, you'll see that the usage shift is even more pronounced on my side of the pond. I can't really explain that either - but it's obviously a matter of "idiomacy", not "grammar".