Years back when we learned about the Bludgeon soft tread problem, I looked at mine and it was being damaged. I removed the soft treads from my Bludgeon, Banzaitron, GDO Megatron, "Gigatron", and Cloud Megatron. Ever since then, I've been wary of the soft plastics. I've always stored my blast effects separately since then.
Hard to see, but the big circles on the legs should be smooth. They have divots melted out from the treads.
Every now and then when I'm toying around with an older figure, I'll notice a pinned joint made of soft plastic against hard plastic that gets a little stuck. I can pop/snap it loose, but I know it's melting. I can't think of any examples off the top of my head.