Worth noting that the supply chain could have a mix of old and new stock, stuff could have been sitting on a shelf for a while in some areas.
As for the change, the base design may be the same, could just be the recent (and ongoing) worldwide component shortages have led to a tweak that is causing problems.
I'm still quoted lead times like 34 weeks for basic passive components, whilst the same headline value may be available elsewhere when you check the details they don't behave in the same way. Even the huge consumers of such components are having to buy stock up to a year in advance to secure stocks.