Condensation- water dripping on the eggs- can & will drown them. You MUST always prevent that from happening.
"I placed paper towels over them to try and remedy this."I don't see how soggy paper towels will help either- maybe you can angle the flex-seal so the water drips off to one side & never on the eggs.
Sad as it is, eggs may go bad for so many reasons...it's part of the breeding game, but you're right to seek to correct what you can. Good luck, the second clutch looks good so far...with one exception, of course.