Not a lead heat problem with my off-center mold, I have been casting for 50 years and know the process well, my mold is really off center, I have seen in reviews of Lyman molds that others have ended up with a poorly cut mold as well.
I have around 1 dozen molds of different sizes, this mold is the only one that throws a cockeyed ball. I find the new CNC lee molds to be as good as any and cast a very consistent ball. The best mold I ever used was a .395 Rapine mold that I borrowed from a friend before I bought that size for myself.