Well, I have been struggling with this Domains, because I work on to try and decide what to put the Domains and Whenever I delete or add. It does not update.  It also show some kind of werid is that the Domains does not delete at all. 
In the Symbology, I always go there and change each field. Some look ok. Some look really stange.. 

I delete No and Yes in the Domains and then add No Orthomosaic and Orthomosaic. Does not update at all... 
Even though, I delete the 4 symbol classes and then add

And then I clicked on Add unlisted values
 


This above screen should be show up on the Symbology when you immediatly change to Orthomosaic field.  and it only shows 4 classes.  
It doesn't remove at all...