I had this happen to me on my old two door, i thought it was just because i was ballsy and put a 4" enforcer on a two door and the geometry wasn't right. I don't own the jeep anymore so no harm no fowl, but just wanted to throw it out there that this happened to me on an evo arm also.
My point for bringing this up was, no manufacturer is perfect, i hope you get good customer service and your issue resolved.
That would be the first I've ever heard of a Currie Johnny Joint (what EVO uses) to blow out like this. Granted, I just run a DTD with 14" of vertical travel so maybe that's why I've never seen it happen before.
No manufacturer may be perfect but unlike you, the problem the OP is having isn't the first that I've heard. Of course, what would I know.