I don't know if it means anything but the male on the nest where I saw the female spawn is eating food but the male guarding the other nest will not eat.
As you're probably thinking that may mean the male is done with his nest guarding duties, but if that was the case you should see some fry. Is it possible he ended up a tardface vs. the other one?
Any way you can hang a light bulb or flashlight over the pond at night to see if any fry collect under it? In the early stages they are very, very, small and you can only detect them with a light. The light wouldn't have to be there very long.
