Three pages of replies, you probably have your answer.
My question is are you stopping to admire and examine your bullets as you cast? Pour, cut and dump just as fast as you can, don’t look at the bullets .
I purchased a new mold several years back and couldn’t find air to try it out. I warmed everything up including the mold on a hot plate. I kept looking at my bullets and mostly wrinkles. I was sure there was something wrong with the mold. Then I read something somewhere and it clicked. It doesn’t take long for a mold to cool down.
I have and currently use a bunch of indoor range scrap. It has everything in the world in it which I think contributes to the mix. You can find just about anything in there but it cleans up nicke although a mess getting there.