Usually most causes of RMS failures are just age and wear of the rubbers, especially if low quality oils have been used or intervals have been exceeded rather regularly. An 8 year life for a main seal over a rotating assembly is very standard, anything higher is a due to be a great success.
BMW engines' also run hotter coolant temps than other manufacturers which cause accelerated wear and tear on plastic and rubber components.
A second cause may be due to an excess of crankcase pressure caused by a plugged PCV system. This would create a pressure differential between the crankcase and atmosphere causing the front and/or rear seals or any other seals to weep. I can't really determine how an oil change could fail the RMS (source; I'm a mechanic, but not a BMW mechanic )
I'm likely to bet that a skilled mechanic with a good eye can inspect your engine and find many brittle/dry cracked hoses and other failed seals.

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2003 4.6, esotril blue, over 215,000KM. Every previous owner failed to keep up the vehicle maintenance. Restoration project.