latex not curing at the bottom?

Hiya, quick question

I'm casting my first latex pawpads and I'm having somewhat of an issue with the latex curing, but only on some of the pieces. My mold is made of oil clay since I only needed this one pair so longevity of the mold wasnt an issue. Some of the pieces have come out just fine, but others are cured on top but still quite fluid on the bottom, the "face" of the pad that you'll be able to see. They're all about the same thickness and they all used the same latex/paint mixture and they were all done at the same time and have been left in the same place to cure.
The only thing I can think of is that possibly some of the molds were hotter than others, since I heated the clay up to soften it quite a bit and poured in some of the latex while the molds were still very warm.

Any suggestions on how to get the two slow ones to cure properly? I want to stick them in the oven for a bit, but I'm afraid since I'm using an oil clay mold, it would just melt the mold out from under them, or soften it enough to do wacky stuff with the curing latex like bond to it or something.