RIR laying embryos?????

[Ruffian]

I have 2 Rhode Island Reds...1 is going on 3 years old and the other is going on 1 year. They have layed fine up until about 2 weeks ago, now I am getting (what looks like an embryo) in the nesting box. I also have 2 White Leghorns that are laying fine. I haven't had an egg from the RIR's for about 2 weeks. I can only assume that this embryo looking thing is coming from one of the RIR's.
They free range and all seem to be fine...any help????

 

[Chicken Outlaw]

Is it like this?

https://www.backyardchickens.com/forum/viewtopic.php?id=473989