Silicone caulk paint no longer cures on product

We have been using standard tubes of silicone caulk (GE brand) for years to paint our silicone props and masks. We typically mix pigments from factor 2 into the caulking and thin it with odorless mineral spirits to airbrush and splatter paint the products. Every so often we would run into a batch of caulk that would not cure on the products and we would have to wipe it all off and find a different lot# batch to use. Recently, we ran into that issue again, and have tried different batch #’s with no success. We tried 4 other types of caulk that also would not cure on the product. It sets up in our mixing cups just fine, however. We are stumped. We thought perhaps that with the supply chain shortages they had to switch to a different chemical in their caulks. We recently just tried using Psycho Paint from Smooth-On and had the same issue. Our silicone that we cast the products in has not changed, and we are using the same methods to clean and prep the products…a 99% alcohol bath and soap & water.  Any thoughts?