Ooh! Ooh! I have some!
It was about 77F in the kitchen yesterday afternoon, but I needed to make bonbons, and I wanted to make them fast. I cast the molds and immediately set them in the cooler, before they had even start to set. I'm guessing this was where I made my mistake, because a few mornings earlier I made several rounds of larger hemispheres that got a brief chill and came out fine, but were chilled after they looked set (and it was only 71, so there was a smaller temperature difference). I noticed a few of the cracks as I was filling the molds, put them back in the cooler to set the ganache, capped, and turned them out to reveal a mix of about half cracked and half not cracked in both of the molds. 33 to sell, 31 for management to eat. Ouch. Just when I start to think I know what I'm doing, chocolate has a way of keeping me humble.