Manufacturers supersede part numbers for many reasons: engineering changes, supplier or supply-chain changes, part consolidation across models, packaging or catalog maintenance. The existence of a newer number establishes only that the catalog now points somewhere else.
A superseding part number does not, by itself, establish that the earlier part was defective or that the change was made to correct a failure mode. Fitment and supersession must be verified by VIN.
What would raise evidentiary value: registry invoices identifying which part number was actually installed, dated before and after the supersession — documentation, not inference.
If your repair order or invoice identifies the evaporator part installed in your BMW, that single line item advances the record.