I would contact Optimum about this. I purposely kept one of the newer formula bottles of Optimum Polish that I bought over a year ago and it's still very smooth unlike one batch of older formula OP bottles I had. The weird thing was that I went though a couple bottles of their older formula without issue, but those bottles didn't sit idle that long so maybe that's why they worked so well?
I still buy and use Optimum products and in fact just placed an order for more Optimum products (OP, OC, OHC & OPS) within the last couple weeks from both Optimum directly and Autogeek. I've only recently started using OPS (Optimum Poli-Seal) in the last week, but I like the initial results I've had so far.
