Ask HN: A bug in WhatsApp?

I checked this on iPhone 5s.

You have a contact saved in your WhatsApp list. If you get a message from him, the name that pops-up as notification on your iPhone would be the name HE has saved in his profile and not the name YOU have saved in your contacts. ( I feel his profile name should only pop-up when I don't have his name saved already)

In my opinion, this is a bug but a friend of mine didn't feel so, hence the question to HN community.

What do you think?