As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MICHELIN AIRSTOP TIRE TUBES HAVE BEEN EXPERIANCING A NUMBER OF VAVLE CORE FAILURES, THE VALVE CORES ARE BEING INSTALLED TOO TIGHT AT THE FACTORY, WHEN ATTEMPTING TO REMOVE THE CORE, WE HAVE HAD 4 TUBES WHERE THE VALVE CORE BROKE APART.