Is a valid EpicGames subdomain?

I received an “Unreal Engine user research: AnswerHub and Forums input needed” email from a domain email. They ask me to sign NDA, but NDA requires a bit more personal information then I’m comfortable to share with sketchy subdomain. There is not much info about that subdomain in the internet - just few Fortnite DMCA complaints.

I can assume that Epic Games gives this kind of emails to their subcontractors, but it would be nice to have some confirmation from them. Or from someone from community. Thank you!

I’ve also received an e mail from them. Any idea who they are?

I don’t know, epic didn’t answer me on this.
I decided not to risk and opted out of any interactions with them