Arley, I wouldn't stress too much about it. Just a bit of casual parts browsing online showed that this is a common-ish part to break. I also see that there are upgraded shafts available. A couple places listed this as a "sacrificial" part designed to give way before more expensive driveline components fail. I would take that with a grain of salt but not totally discount it.
In my experience with my larger than life mudding 4 wheeler years ago, most of the time you tend to find the parts that need to be upgraded rather quickly. Mine was a Polaris 850XP, a 71 HP unit, with very large tires and slightly lifted. I had to upgrade the front axle shafts due to frequent breakage. The upgraded components never broke, nor did any other driveline component fail because of the upgraded axles. That's not to say it's the same issue, just trying to be supportive. Shock loads, high traction reversing, or extreme angles were typically the culprits for mine. Not the same part though so you shouldn't have to worry about the extreme angles. But still, reversing under load with the wheels (tracks) turned to lock could still cause a potential for binding, adding increased strain to the front drive components.
I bet you have more traction on the front than the typical user because of the tracks. Me personally, I would be mindful of that fact when you get the warranty replacement back, then if it happens again install the upgraded shaft.
You have a serious unit there. I like it.
