Compared to the plastic in my old 5ive bumpers the xmaxxs plastic is indeed a lot more rigid thus meaning they will crack more often. A hell of a lot of force does go through these when there landed on however.
Diffs are luckily cheap fixes but annoying if it's going to keep happening, maybe back your slipper off a quarter turn. The guy on Facebook running 22/50 has also just broke his front diff. Kinda annoying they haven't used large 1/5th side CWP's, these are close to 1/8th size which we know aren't reliable. A machined set of diff gear will be a worth while purchase if they become available.