Odd bulge on eggs?

[AloneNTheGarden]

I have a RIR hen that is about 2 years old and has laid eggs with the same issue for about a week and a half. They all have this odd, small bulge that is very weak and easily cracks compared to the rest of the shell. The spot is always about the same size on each egg. I tried researching on my own, but could not find anything quite like it online. Some of the eggs have also had wrinkles, but not all. She is my highest in the pecking order and is still acting normally, still the top lady, and I’ve given her a full comb-to-toe exam and not seen anything suggesting she is ill or there is anything wrong. Droppings are normal, eating and drinking has been normal, no major changes to her environment other than it’s getting colder/darker here. She is free ranges during the day, cooped in the evening. Feed comes from our local mill and she has access to oyster shells at all times. BSF larva and healthy scraps as treats. I did notice a few pin feathers around her head/neck which suggests she’s heading into molt, but other than that things seem good. Has anyone seen anything like this? Is it just due to molting?

 

[Sally PB]

Are the eggs normal on the inside?

 

[aart]

That's an odd one for sure.
Have seen the 'weak' spot, I assume the shell is thin there?
But never before bumped out like that.