First I've seen something like this.
A user is sending an email to someone, and the person receiving it cannot reply because the email address it's coming from appears to be a donotreply address. I've looked at their Google account where I can (update user, user information, etc.) but cannot find where this donotreply is coming from, nor why a recipient cannot reply. My next step is having them send me an email and then seeing if I can/cannot reply. Perhaps it's just a visual thing (strange and need to resolve it) and I can still reply, or perhaps it truly cannot be replied to..
Thought I'd check here to at a minimum clear up the donotreply portion.
Vault:

Screenshot from user's phone it appears.
