A day after I noticed Grape-Nuts cereal was grayed out for out of stock on Instacart, this popped up on my feed:
https://www.usatoday.com/story/money/food/2021/01/27/grape-nuts-shortage-breakfast-cereal-supply-coronavirus-demand/4259281001/
Grape-Nuts will be available again sometime in March 2021.
They're sort of a perfect prepper food, energy dence, compact, can eat hot or cold and with or without milk.