In the word "french" C H is pronounced sh and nobody bats an eye, I don't think it's that outlandish that someone once read it as fuch-sia, incorrectly splitting it compared to the original.
In the language French, fuchsia is unequivocally read something more like few-shia, and I'd bet that even though it comes from German Fuchs-ia (fooks-ia) English has picked it up from the French side.
If you find such a loanword weird, don't you dare try reading Japanese.
https://aethermug.com/posts/the-beautiful-dissociation-of-th...