How do I exclude files ignoring case sensitivy?

[nemonein]

I'm on Archlinux, fd's version is the latest.
Please take a look the the below.

$ fd -t file --exclude "*.mp3"| rg mp3
aaa.MP3
bbb.Mp3
ccc.mP3
....

I think aaa.MP3, bbb.Mp3, and ccc.mP3 should be excluded, but those are included.
Is it as intended? I added --ignore-case option, but the result is the same.

I can get what I want with other utiliies(such as rg or grep), but I guess fd could do this alone.
Any help would be appreciated.