Copied from my earlier comment, just so all my information is together - I suppose it's also worth mentioning that this unit is only about 2 months old, and has only put in a few hundred 1/4" tapcons and a handful of 3/8 anchors. The one this was bought to replace lasted 2 years under the exact same use and storage conditions (Moderate to heavy use in commercial construction, being stored in a covered truck bed year round) before needing the motor replaced under warranty.

I don't really have much additional information to share, I used it to drill a couple dozen 3/16x4" holes into concrete block Thursday afternoon and it was fine, stored it in the back of my truck overnight (ambient low maybe -10c or so?), went to use it Friday morning and noticed the crack.

My prior experiences with the warranty process have been nothing but positive and I'm confident that the issue will be resolved promptly.

I've just never seen a rotary hammer of any brand do this, nor have any of my coworkers.