What temperate are the corn eggs being incubated at? The temp swing will most likely be a shock if you pulled them, I'd think. I've successfully incubated corn eggs and ball eggs in the same incubator, but personally I wouldn't risk a corn clutch for one egg that is MAYBE fertile. Temp swings aren't good for eggs, as far as I know. Spikes can cause kinking, which I've seen for myself. Not sure about drops.

When I did corn/ball eggs in the same bator, I anticipated that this was going to be happening. I set the T-stat to 86.5. The extra 1.5 degrees either way didn't do any harm to the snakes in the eggs. The corn eggs hatched on day 57 instead of the usual 60, and the ball eggs hatched on day 58 or something. So while I've done it before, I won't do it again, as I now have 2 separate incubators.

Either way, I hope that one eggie is fertile for you!