Having worked for Michelin on the customer side, MOST problems are caused by customer use. They cannot say that, but that delamination comment from NMDan is probably right. It is possible that the butyl lining was not attached properly, but the most likely option is that it has separated from the tyre because it was run at low pressure, overloaded (samething) or overheated.
Guessing from the photo.
It is delamination, but you guys should note that this is on the inner most layer! Besides, have you heard of this happening with the other brands?Delamination. The cause usually is at some point in it's life it was run low on pressure, overloaded or overheated.
As for manufacturing, let me describe the general process for you! It starts with forming a tall cylinders of "green" rubber layers. Each layer have the composition that is designed for that depth of the tire thickness, such as cords, steel belting, or pure rubber for the thread. Each layer has a solution of catalyst/adhesive applied. This is where thing went wrong to cause delamination! If the coating of the catalyst/adhesive being applied is spotty, or insufficient, then you will not get good adhesion in between layers after molding!!!
When the, very hot, mold closes, it bulges the center of the cylinder into the outer most part of the mold, and high pressure is applied inside the green rubber cylinder to force the rubber layers very hard against the inside surfaces of the mold and held until the rubber have melted into the outer profiles of the mold geometry and fully cure. From distance memory, that takes at least 15 minutes, or 1/2 hour. Back when I was working at Firestone, in my youth (part of requirement to get an engineering degree in NZ), they used high pressure steam to both heat the mold and pressurize and heat the inside of the "green" rubber tube. They were in the process of converting to electric heating of the mold, for better control the temperature profile at the time, and that's how it's probably done nowadays.