Quick Google Search found the ingredients.
Coconut Fiber, Composted Forest Material, Feather Meal, Fish Bone Meal, Guano, Gypsum, Greensand, Kelp Meal, Mycorrhizae, Non-GMO Alfalfa Meal, Organic pH Adjusters, Peat Moss, Perlite, Rock Dust, Rock Phosphate, Soybean Meal, Wormcastings.
Since I’m just guessing and not advocating letting those larva grow up just to see what they are, I’d say they’re some type of fly. More than likely the issue would be in their worm castings. It could be from low quality compost too though. If it’s not allowed to reach proper temps for a length of time.
You definitely don’t want them in your soil tho. I’d get some neem oil and yucca powder to water with for a little bit. It should do two things, suffocate the larva and protecting your roots so if they eat at them it gums up their mouths.