When I've incubated snake eggs, I've always separated them shortly after they were laid: never lost any by doing so, but it does take patience & a little time.
I dripped (from my finger) one drop of water on the point of contact, then slowly & gently rotated the eggs slightly back & forth (keeping the same orientation)
until the contact point finally released all the way. When I've had a dud egg go bad, they not only got moldy, but they also drew flies -tiny ones that move in
and can also affect the surrounding good eggs...so by having them separated from the start, it was EASY to just pitch an egg that went bad. Just my 2 cents...
The mold may not affect the good eggs, but the flies certainly can...they start families.