37.5C or 99.5F.
They can't potentially hatch unless the temp is above 35C
At your temp, they aren't even getting cell division. That can't happen below 27C and above that there will be disproportional development till you get over 35C.
Is it a fluorescent shop light? If so, they don't generate enough heat.
If it is a 100 watt incandescent or halogen lamp, the problem is thermal stratification.
Heat rises. Your heat source is at the top and the eggs are on the bottom. The heat won't go down unless you have strong fans to pull it down.