What’s on my cleaner shrimp

[Glenng78]

I have a skunk cleaner shrimp, and have noticed a large yellowish disc on his body. It almost looks likes some type of calcified growth. Any idea ?
sorry for the poor lighting

 

[Idoc]

Hard to tell exactly by the picture. But, has the shrimp molted recently? If he is acting normally, then I would monitor him and see if it goes away after he molts again.

 

[Glenng78]

It’s been there ever since his last molt. I don’t remember when that was , probably a month or so