It's kinda hard to tell with these test going off, but the reply is to the person receiving UFM. They get a notification on apps that support them, and it shows up in their reply tab.
I do have to fix the comment and add a mention, but I didn't code this bot. I'll have to dig through the code to see exactly what needs to be typed in to get that to work properly. It's on my list of things to do this week.