Adding my Band 2 to the list of split straps.
I got my Band 2 day one--shipped directly from microsoftstore.com.
It's sized correctly according to the sizing guide. I wear mine a little loose--there is roughly 1/8-3/16 inch between back of face and my wrist if I pull on the face. I can't get my pinky finger between the Band and wrist.
I loosen during workouts and slide up on my wrist, above my wrist bone. I find the HR tracking is better there.
I wear my Band face down.
Use a computer 8-10 hours a day, so it is often pressing on the wrist rest throughout the day. Noticed it flexes at the point where the crack is when I rest on the wrist rest.
I do not leave it sitting in car or sunlight, unless it's attached to me and I happen to be sitting in those places.
I use mine for exercise--gym, hiking, and biking. I wear mine all day, including sleeping. I only remove for charging or showering.
Just doesn't seem like unusual uses and definitely not something that would lead to cracking.
I called MS support and they agreed to replace. No argument whatsoever and they didn't require any picture ahead of time. However, they tell me they will only provide a refurb by mail. I told them I wanted a new device given the cost and timeframe that this occurred (<6 mos). They said they can only provide a refurb. That was disappointing. I know I can get a new device if I go to the Microsoft Store (did that with Band 1 for the third replacement), but it's a four hour round trip drive for me.
By the way, I wear a Fitbit Charge (so can compete in challenges with friends and family) on the opposite wrist and it isn't suffering from any strap cracking issue.
This may be my last Band purchase after three exchanges in one year with Band 1 and this issue cropping up with Band 2. I love the Band, but Microsoft just can't get the durability right for such an expensive device. While I'm not crazy about the look of the Fitbit Blaze, it is beginning to look like the better fitness tracker option, assuming similar durability to my Charge.