Grammar, Usage / How to use "mystified" in a sentence [3]

passive voice misuse

Hi everyone,

I used a website to check the writing grammar. I have a result like this: "passive voice misuse.".

"This is because scientists and the public have been typically mystified for years about whether aliens exist or not."

But when I replaced "mystified" with " confused ", the sentence was correct. Could you please give me a good explanation, please?

"This is because scientists and the public have been typically confused for years about whether aliens exist or not."

For your information, I attached a screenshot of the website.

Thank you!!

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