Welcome to the forum. Do you have any pictures of her when you got her and then compared to today. It would be easier to offer an opinion with pictures.
You might want to read this article on bengal kittens changing color.
https://bengalcatclub.com/bengal-kittens-change-color/ and that may be the article you've already read
If that doesn't answer your question, you might want to ask your breeder who would be much more familiar with this. However ... I would not think a bengal kitten would turn grey of all colors. Bengals are not grey in color. You might want to look up food deficiencies in cats and see if something hits with that. When all else fails ... you head to the vet for their opinion.