Beemer530i

I have a 2001 BMW 530i M54 3.0i Petrol engine - just done an oil change etc and in the undertray are 7 small roller bearings loose!! No loose pulleys or bearing rumbles from pulleys or pumps - no visible signs of bearings missing or noise.
Any ideas ? Clutch fan has a tiny little bit of front / aft play but no signs of missing bearings etc or frayed belts.

Any ideas where roller bearings would / could come from ? After replacing oil etc - cleaning up and test run found one - roller bearing i( it is about 6mm long and 1.5mm wide ) in tray again but no leaking oil or any metal in oil sump

Any suggestion please ?

Regards Gary E