In combination of limited testing, and modern economics of extracting profits, changes are made to organizations and products all the time. It happens left and right.
I work for a company where substitutions have to be made on a continuous basis, because suppliers of parts run out of raw materials or components, raise their prices, and/or can't deliver; yet demand for the product continues, and 'the show must go on'.
In a market as specialized as backing paper for 120 film, I would be willing to bet that keeping a steady supply is a challenging enterprise. There may be one or two suppliers in the world that can do this, and I'm sure they have suppliers too, providing things like ink, coloring agents, raw paper material, and the like, and they will in turn experience supply issues, ad nauseum.
It may also be that Kodak Alaris simply doesn't have enough resources to deal with situations like these as effectively as Eastman Kodak would have in the past.
Finally, one might argue that it would be a good idea to develop a Plan B for these kinds of situations, in a system of redundancy have a 'next best alternative' to a current working solution, so that when the bad news happens there is sustainable recourse.