This was the follow up:
I received a call from: BMW NA Customer Service
I talked talked to Liz.
She listened patiently to my concern. Since my ticking has not returned after the dealer did the bleed procedure a year ago, BMW is considering this problem as resolved for my vehicle. She also told me that maintaining the vehilce at the BMW Service Center according the prescribed maintenance intervals should reveal any annomalities at an early stage. I'm still crossing my fingers that the ticking will stay away... It just scares me to see 38 pages from people with metallic ticking issues.
2013 X5-35d - Platinum Grey / Oyster; Premium - Sport
2007 BMW ///M Coupe
RETIRED 2006 TiAg E90 330i - Black leather - Alu Trim - Prem - Sport - NAV - Step - CA - Heated Seats