Deaths proud isn’t working as intended. It will fetch a land after destroying an opponent’s target creature. But that land does not receive any mana. It is supposed to be filled with mana and ready to cast
I just used it the first match of AJTH: The Space-Time Catastrophe and it worked as written. Maybe there was something in play that prevented cards from gaining mana?
I tried it on the left node of Awakened Inferno and the land it fetched did gain full mana. It is working fine for me too
Hello guys,
Thank you for all the information provided, this issue will be investigated!
If you have any additional information that you consider relevant, please don’t hesitate to send me 
Rebeca.