I thought that it just showed all addresses in an HD wallet. Does it make mistakes sometimes?
As far as I know, you can't see if addresses came from a HD wallet. The addresses come from the private key, and it's the private key that is created in the HD wallet.
I'm no expert, so I'd like to be corrected if I'm wrong on this.
Wrong. You can't derive a list of all addresses from a HD wallet unless you have the master public key/xpubkey.