@Introvert my guess is bevause she was spirited away. So the butterfly did in a sense kidnap her.
I haven't looked at the source but I wouldn't be surpass if they use the word for spirited away/ spirited kidnapping. So translating it would make more sense to just use the word kidnapping and would need less explanation. Old fairy tales use to mention even in English text that the fey would kidnap mortals, but modern stories have moved away from the Trixie and mischievous fey. Modern spirits in main stream media tend to be portrayed as kind, helpful, and/or playful things. Or children off off on a fey adventure are returned at the end. Which doesn't always happen in old tales.
But that's just my thoughts, and my excuse to ramble about old stories.
I haven't looked at the source but I wouldn't be surpass if they use the word for spirited away/ spirited kidnapping. So translating it would make more sense to just use the word kidnapping and would need less explanation. Old fairy tales use to mention even in English text that the fey would kidnap mortals, but modern stories have moved away from the Trixie and mischievous fey. Modern spirits in main stream media tend to be portrayed as kind, helpful, and/or playful things. Or children off off on a fey adventure are returned at the end. Which doesn't always happen in old tales.
But that's just my thoughts, and my excuse to ramble about old stories.