I had the same problem on my 530i. Not only did it burn through the leather but also a hole in my $2500 suit. I got the leather replaced and compensated the full value of my suit which was fairly new so I still had the receipt from my tailor.

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-2006 E53 (X5 4.4) Titanium Silver, fully optioned (sports package, premium package, navigation, ride height adjustment, panorama moon roof, rear climate package). Aero kit installed plus set of staggered 20s with Diamaris tyres.