So today I met this level 4 guy. He was a nice guy and we started to become friends ( I think). I told him I was going to add him and give him tips so he can get better but when I tried to add him I couldn't type "_" when I was typing his username on add friends. His username is Smoke_n_Thunda. Try adding him or typing "_" and see for yourself.
I thought I brought this up before in a thread but I guess I forgot to. This is a legitimate bug that should be looked into because, while there aren't many people that use underscores in their name, it's annoying when you can't add someone because of it. On the other hand though, if you have one, you won't receive random friend requests from people, so there's a perk to it as well.