First, I want to remind you that when Kodak said they had addressed the backing paper problem with TMY they did not say that they had fixed (= identified and eradicated) the problem. They rather said they had taken steps to ensure to minimize the chance that this problem would occur in the future. Such a statement clearly does not rule out the possibility that the problem could still show under certain circumstances and my guess is this is just what happened in the recent, alleged "post fix" case reported by a forum member in this thread. Also, as far as I am aware, they never made any official announcements that claimed film from certain batches was "affected" or "safe". All lists of batch numbers affected or announcements that claimed that the problems had been fixed with certain batches were put together by individuals.
Second, incidents of problems with backing paper HAVE occurred in the past, before Kodak's recent great backing paper blunder, and will probably continue to occur in the future. Issues like mottling, ink transfer and others have been reported from manufacturers Ilford, Foma and probably others. I personally have had this issue with some Ilford FP4+. These incidents have been mostly explained as a isolated "freak" cases, caused by adverse storage conditions (humidity, heat) or improper handling. This is important to bear in mind, because unlike some drama queen suggests, we have NOTHING at hand that supports that the recent problem reported here is more than just THAT, namely an isolated, single incident of a backing paper problem caused by adverse conditions. At least with me the word "Amazon seller" is not exactly causing associations of credibility and trustworthiness. To be fair, except for the claim of the poster, we haven't even seen any evidence indicating that it is "THE" backing paper problem AT ALL. Let me remind you that there have been reports of backing paper numbers showing on pictures in the past that claimed to be caused by THE backing paper problem and later turned out to be rather caused by irregular exposure through a "ruby window". So, at least as far as I am concerned, until we get further evidence, the verdict is still out in this most recent case.
My personal, completely uneducated guess is that the reduced ink backing paper introduced by Kodak 1 1/2 years ago was just a short term, easy to implement countermeasure that Kodak came up with while they were still in the middle of identifying the root of the problem. I suspect that if there is any "fix" in the sense of the word that the original problem was isolated and corrected, than it is in the new TMX backing paper, and I would not be surprised to find that this backing paper is also introduced with the remaining types of Kodak film over the next months.