Lumpy’s got it right, it’s the high temperatures that did it to you. Ninety degrees F is the HIGHEST a developing embryo can tolerate safely. People who incubate at this temperature are taking a major risk because any kurtosis (variability of the thermostat) can exceed the thermal tolerance of the developing embryo and lead to uneven growth in whatever tissues were developing that day, or accelerated growth that day when other days tissues grow more slowly.
I personally incubate at 88.5F to play it safe. You can incubate as low as 84, honestly, it just takes an extra 7-10 days to hatch.
What kind of incubator do you use? If it’s one of the minifridge incubators, toss it, they’re trash.