Delirium monsters don't spawn in Incursions

As the title says, Delirium monsters don't spawn in Incursions anymore for some reason. Unlike Harvest, they already didn't have the little pods and pustules that spawn monsters when stepped on, and now they don't spawn from the ground in ordinary fog anymore either, which worked fine last league. Running Alva + Delirium + Beyond was one of my favorite Atlas combos because it was a great way to get ilvl 84 cluster jewels.

Nothing in the patch notes, so I assume this is an oversight, not a deliberate shadow nerf (lol, fat chance).