Hi @swedishcow,
Thank you for reporting the bug regarding card “21039” (Cosmic Awareness).
However, we do not consider this a bug.
As we discussed here, we believe that the “Remove 3 threat” part is not a cost in this effect. When you attempt to discard more cards than are available in your deck, the cost is not met, which prevents any threat from being removed.
If you have any further insights or questions, please let us know.
Thank you for your understanding!