it's mainly user error - much like the SXK Billet. Mine is fine, but I already knew what to do, and what not to do. These are the "biggies":

Over tightening the drip tip adapter/ locking nut. - A huge issue, a does not need excessive tightening. SNUG is a good term, tight is asking for issues.

The next one is Double wrapped batteries. These stress the back and side walls of the battery compartment, and is my only hairline crack location on my Billet...caused by "fancy, matchy-matchy double wrapped cells". Remove the original wrap if you want a new color battery!

I don't buy the "low ohm" excuse...this is another vape "myth", just like "adding/removing a wrap on a coil"! Low ohm builds are usually less hot overall, especially considering the small coiling area allowed on most bridges...there simply isnt enough room for big, bulky hot coils, so most of the heat is from high resistance builds, "resisting" electricity flow. This isn't a real issue, and is an excuse, partly to appease angry customers.

Sure, anything's possible, but it's mostly user error. We knew this was going to be a thing - Billets are for the top-tier of vapers, which directly clashes with the idea of Billets being "the new hotness". Hurt feelings will abound!

I wouldn't worry too much if anyone hasn't experienced any cracking on their device. Be careful, only snug up the top, and Don't drop it!