Kinda looks like phenolic used in chain guides. Or whatever plastic they use now. Could it be from the filter itself? The shavings look like copper. A rod bearing would look like that and also make a knocking noise during operation.

Use a magnet and see if the shavings are magnetic. Also run a magnet through the oil and see if you pick up finer material.

I second the idea of not driving it if it's making noise. Hardware engine noise quickly turns from a $100 fix to a $4000 repair if driven too long.

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2005 X5 4.4i SterlingGrau, Sport Package, DSP
Build 3/12/2005