Any question like this omits reference to the fact that problems with backing paper relate not just to the paper, but rather to the interaction between paper, particular film emulsions, available paper, and paper and ink printing methods and materials.
This is why Eastman Kodak's issues aren't/weren't the same as Harman's issues, which in turn wouldn't be the same as any issues experienced by Foma - all because of a number of factors, including the differences in the films themselves.
Eastman Kodak only ran into problems when their years long excess inventory of previously manufactured backing paper finally started running out, and it became clear that what were then current printing and paper manufacturing materials and equipment and methods were incapable of duplicating the old materials.