Don't let anyone kid you, Trex does split and crack. It MAY outlast treated lumber, that remains to be seen. I have Trex decking on a pressure treated frame. The decking is splitting, about 10 years old. Not a bad life, but will not last forever.
Your are the first I have heard of failure . Probably the earliest of the production were better made and the demand has been compromised , I would notify the manufacture.
There was a batch , brand , not sure which manufacturer it was , that came out a few years back , and it was prone to splitting , a lot of it was replaced by the manufacturer .
Every thing in manufacture is prone to failure even trees split in the woods. If I were building a home I would strongly consider recycled materials not that I'm a greeney but I have been recycling all my life . long before the word was coined. As a kid in the 50s the neighbors gave us cast offs all the time and we even picked stuff out of trash cans we valued. neither a badge of pride nor same , I think of my self as NOT WASTEFUL . probably why I learned how to fix every thing.
Yeah, my neighbor threw out a perfectly good Honda engine on an old brokeback mower frame. I asked for and received the engine, Change the oil and mounted it to a Murray frame, Cut 1/2 off the blade and Franken mower throws grass sticks and rocks. It's like a lil Bush hog