what is this all about?Is this normal?both front sides developed this exact pattern..rears have a slight purple tint to them ...I bed them in tonight ..8 stops from 60mph-20mph...let them cool down after every session...did it 3 times..total of 24 hard stops...no squeal, smoke or shudder..i was wondering if the caliper might be the culprit.

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2006 X5 4.8is LeMans Blue / creambeige interior
Prod.date: 2006-06-21