I was on a mission where I got Goo thrown at me and Worms. The problem is that when you have Goo on you the Worms are there but are hidden under the goo. You can target them but can’t zoom in to make sure your reticle is right on them… All you can see is Goo.
I’ve encountered a similar bug where worms can hide 'inside the corpses of other worms, rendering them untargetable and immune to explosions.