some molds can be temp sensitive.
sometimes they want more heat and then they drop their bullets like a hot tater.
[had one of them today, at temp you just opened and wiggled the mold, a little cold,, crack with the wood on the hinge]
other times you stand around like your waiting for a bus then they fall out on their own, they are a pain because they still want some heat to pour a good bullet.
got a 41 mold like that, if you try to dump the bullet out too soon it just tears the top drive band, if you wait for a 10 count after cutting the sprue they'll roll right out of the mold.