I do not know if this was fixed because I have not been playing SR a lot recently, but I have had this bug happen to me twice. If you happen to pick up the Rift Herald at the same time that you use a dash or blink, the chat will say it's normal message, but instead of a champion in the parentheses, it will just say, "()", and no one will have picked it up. I have had this happen with Yasuo ult and Kha'Zix e (I think), and it is really defeating having fought over herald, win, and then not even get a chance to summon her.
1. Kill herald.
2. Use dash or blink on/over the pick-up (I do not know how finicky this is because it's only happened twice).
3. No one in the game has picked up Rift Herald.