After lurking for a while I finally pulled the trigger and setup a small cuttlefish tank. After cycling and running the tank for a few months with a pair of chromis and some assorted macro I ordered some bandanesis eggs from bluezoo. The eggs arrived 2 weeks ago and appeared to have no issues and after acclimating I added them to breeder net. So far none have hatched but this morning when I woke up I noticed a single egg appears to have a relatively large clear bubble growing out of it. It doesn't appear to have any holes in the egg or bubble from anything hatching and I haven't seen movement in the bubble while the main egg remains black. Does anyone have any idea what is happening or what caused the bubble? Is this normal? Google found a few vague references but nothing really detailed. I've attached a pic but the photo is bad through the breeder net mesh.