He probably has not had her on post transition. It's possible she appeared on the channel before transition, eg. as "Daniel Fore" in the past which might be the reason for the confusion.
I know we're supposed to assume good faith here, but I find that really hard to believe.
As far as I'm aware, Danielle didn't "announce" her transition in any EOS channels. But if you look at her profile for more than five seconds, it's pretty freaking obvious. Her name is updated on her Twitter, from which Lunduke based his article:
I would be willing to overlook that kind of flagrant oversight if not for the fact that Lunduke calls himself A JOURNALIST. That he would continue to use her dead-name despite all of the research he's supposed to do as part of his job makes him either malicious or incompetent. Take your pick.