Chaos War just finished fairly recently, and there is currently no ongoing series, published since the end of Chaos War, that is set in Wakanda. The current Black Panther series is set in Hell's Kitchen, and T'Challa is no longer the Panther (officially) so he is no longer -- let's say "attuned to" for lack of a better term -- the Panther God. Shuri, who is the current Panther, basically isn't appearing anywhere, and I'm guessing her recent limited series concluded before the events of Chaos War did. So there's actually nowhere where Bast's death would be acknowledged since the people who would be affected by it -- the Wakandans -- aren't being featured anywhere.