Sands of War...

[MotleyLew]

Do SoW no longer drop randomly in dungeons?

[asheiner]

it still does.
In any case in the Cosmic Frontier dungeon.

[MarkyMark]

Infernal as well. I was running pretty low at the start of the month but after running infernal dungeon plenty for the monthly event currency I've got heaps of SoW again.