Eggs early in development will not have anything moving inside it, and the developing cuttle will look like, well, kinda like a glob of goo. As it grows the cuttle will take shape and you will eventually see the forming.
The eggs with less ink in the case may just have lost a couple of layers so look clearer.
im not sure if they look like this because they are kind of small. but its something similar. they are all over the eggs all the time!! they always stick on the glass as well, i think one of the eggs actually popped because there was this white thing sticking out.