It amazes me that someone that posts here as much as you wouldn't just follow Debs write up on how to make a fool proof egg tub, might of saved you some headaches and possibly a disaster. I'm hoping for the best for you but from now on you might just want to follow her write up EXACTLY. It's been proven to work perfectly for years for many people and really is fool proof. Every time I've seen someone here with incubation problems, it is always a different setup than what's in the write up and I'm not sure if it's because they have not read it or just decided to try their own way but it doesn't make any sense to me, if something has been proven to work perfectly every time, why complicate things? It's hard to miss but if by chance you did miss it, it's a sticky in this section.
Don't get me wrong, of course you could still get a moldy egg following her write up so I'm not saying that's why it happened, but people do seem to run into these situations more often when putting the eggs right in the substrate. When you put the eggs on a light deflector, it eliminates running into an issue with the substrate being too wet which is a possible cause for eggs rotting. This is just an observation from looking at your tubs in the other 27 egg post that you obviously didn't follow the write up and I'm surprised since your a regular here.
I also agree with her advice not to try removing the rotting egg, if anything you may just want to redo the tub according to the wright up just in case your substrate is too wet and causing the problem. Then just leave them. If there is a problem with the way you have the tub setup it could lead to more bad eggs but if your tub is setup right, the good eggs don't get affected by the bad one.
Good luck with the rest of the incubation and other clutches.