(It is probably an upstream issue but I am not aware where to report it so I ask those who know to find it)

My intention is to add user @AS to my herald rule. But when I write his username what I see is

M129 A try to add user AS in a Herald rule by Base

10

I would also appreciate if someone provides me with a workaround for this. (Well, and it looks like an good reason to take a look at Phab's API as a possible one finally, hehe)