Oh, I have, but in a different context. Spent hours recently looking for the Warrior rats in Araz, which you need for the initial Amarr Cosmos stuff. None. Nada. Now, in the past, the drop rates of the essential loot - Dynasty Rings, etc - was low. But now I could not even find them.
Maybe I was just terminally unlucky. However, I also wonder whether they still exist. Would not entirely put it past CCP for someone to have said “What is the point of this oddly different NPC rat?” and removed it, without realising they had just screwed the Cosmos mission. Probably a dev who does not even know what a Cosmos mission is…