Triple Trouble - Wurm Egg Scramble
Im not sure but I think you need to do all 3 preevent paths they spawn diffrent eggs.
So if you keep doing cobalt only you wont get any more
You should be able to get credit when killing eggs on the escort for any of the heads
Send a support ticket.
Some eggs vanish before you can lay any damage on them, go the route you find the eggs last long enough to damage them, usually crimson and cobalt, amber are gone even before they can officially be attacked thanks to the necro trait.