Securing Resources Special Operations: What the heck am I missing?

I'm 15 levels above the recommended level, using a build that usually one-shots stages where I'm 5 levels below the recommended, yet every time I attempt to gather resources within special operations, the enemies are seemingly fully immune to my damage. The red lines of their health bars don't even move, and I'm dead on the first return-hit. What's the trick? I don't get it.