I've used Eco Earth for almost 5yrs now with my snakes and tegus and haven't had any issues. It's not digestible but it's small enough to pass through the digestive system with out any issues. It mixes in with the poop so it's harder to see it.
Any time wet touches dry somethings going to stick, especially with something that's absorbent. Eco Earth is meant to be kept moist. The only time I've seen clumps of it sticking to any of my reps is when they have been in their water and the substrate is too dry.
How low or at what level do you hold the feeder if at all, for the snake to miss and get a mouth full of Eco Earth? I don't lay feeders on the substrate I dangle it until they strike. By the time it's on the substrate it's pretty well covered. Even when they drop it to re position, it's not covered in substrate when they eat it.
@RottsTottsnRepts you can restrain her and try and get it out or let her soak for a bit