discoloration = brown stain
Thanks! Still no smoking gun on a cause, but more corroborating information. Editing the original subject to include "brown stain" (yuck).
2008 135i Sparkling Graphite Metallic - 6Sp - Black Boston Leather - Gray Poplar trim - Sport Package
Premium Package - Comfort Access - iPod/USB - HD FM - Premium Hi-Fi - Heated Seats
5/27 Euro Delivery Welt - 6/5 Drop off AMS - Re-Delivery 8/8 - SOLD 8/2015