>>9451804The joints I had issue with was the Black Lion's hind legs/Combiner knees. There were large pieces of plastic flash there interfering with the hinges. I've already broken away most of it and the knees work fine now.
These grey parts seems to be made out of one of those tougher plastics that are also prone to plastic flash. It's not Nylon, probably POM or some tougher ABS blend.