Which "experts" said Pan F+ has poor latent image keeping properties? I still haven't seen any objective, controlled data presented by anyone, and Ilford does not indicate this is a problem.
As for manufacturing/QC issues, I really don't see how an individual can be as certain as NB23 about something like this, particularly when he has admitted to completely ignoring manufacturer handling recommendations. There are so many variables involved in processing film, from temperature shifts to chemistry mixing practices. Which is more likely: an undetected QC screw-up at Ilford, or an undetected inconsistency, control error etc. in one of our home darkrooms?