Another thought as to root cause...

The fuel pressure regulator is built into the fuel filter.
I wonder if or when the FPR fails, does it allow too much fuel
pressure in the return line to rise let's say from 20-25 psi
(does anyone know the normal fuel pressure in a return line?)
to the 45-55 psi range (which is normal operating range),
causing seal blowout?

For every problem, there must be a cause...

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1998 E39 528i 5sp MT
2006 E53 X5 3.0 6sp MT