为什么是I don't know what's wrong with you?

其实,What's wrong with you?本身就是陈述语序.
英语中特殊疑问句不都是倒装语序,当疑问词在句中作【主语或主语的定语】时,特殊疑问句用陈述语序.所以,放到宾语从句时,句子不需要改变语序.
如 Who is standing there?who作主语,I don't know who is standing there.
Whose father likes music?whose 作主语father的定语,I don't know whose father likes music.
What's wrong?/ What's the matter?What happened to you?都是疑问词作主语,句子都是陈述语序,所以,在宾语从句中都不需要改变语序.
而What are your hobbies?疑问词作表语,句子是倒装语序,所以,在宾语从句中需要改变语序.
希望我的回答能够帮到你,