Sometimes not ubering?

[Tvde1]

Someone told me that they right clicked, and "ubered" did appear in the chat but it did not uber.
(https://www.twitch.tv/neutrogaminglive/clip/RealSillyEyeballOneHand-EBtGB0BXoq0ds0jD)
I don't see how this could happen (don't have a demo/replay) so let's see if it's reproduced