So, I've used TT to seal my pony's eyes since I started doing customs. And I just noticed lately that almost every pony I've used it on that I still have, the TT has yellowed, badly. Like there are one or two that it didn't happen with, but the rest, I had to very delicately peel and pick the TT off. It didn't always come off easily, and now I have quite a few ponies who need their eyes retouched or repainted completely.
Has anyone else ever had an issue with yellowing Triple Thick? Is it an issue of time? Exposure to sunlight? The kind of paint I use (water-based acrylics)? Could a bottle of TT go bad? The bottle I'm using is a few years old, I guess. Should I bother trying a new bottle, or is this just a characteristic of the product?