Apple has launched a replacement program for USB-C charging cables included with MacBooks sold through June of 2015, as well as those sold separately during the same time period. While Apple doesn't mention what portion of the cable is at fault, it says that affected cables may not charge correctly when connected to a MacBook:
According to Apple's post, affected cables do not have a serial number listed next to the "Designed by Apple in California. Assembled in China" label on the cable. The redesigned cables do have a serial number next to the label.
Apple says that it will proactively ship out new cables by the end of February to those who have registered valid addresses during product registration or through an online purchase through the Apple Store. All other MacBook owners that have affected cables can contact Apple Support via telephone, or visit an Apple retail store or Authorized Service Provider to get a replacement.
Master your iPhone in minutes
iMore offers spot-on advice and guidance from our team of experts, with decades of Apple device experience to lean on. Learn more with iMore!