Some years ago Kodak reformulated their films in order to use new coating machines and changed their names. The new names have the film speed indicated first as in 100 TMX. Older stock will have the name TMAX 100 or something similar.
Another example would be new 400TX and old Tri-X 400. The design of the packaging also changed and these changes should have been a flag to re-read the film insert. There were numerous ads and articles in magazines about the change.
So the problem is not with Kodak.