Hi and welcome to NICO Club! No, I haven't had silicone crack. I didn't even know the stuff COULD crack. Maybe it's some similar material, but not silicone? If it's not warranty, then it's up to you to repair or have repaired. Sounds like you might be able to do it yourself if you're up to it. You might try to remove the old stuff and apply some new stuff that actually is silicone, then it shouldn't crack on you anymore. Best of luck!