Muffler Discoloration - Is this Normal?

[650i2014]

Hi Guys,

I tend to inspect the car, especially the tyers, every now and then and I noticed inconsistent discoloration of the right muffler when compared with the left muffler.

The left muffler is basically intact and as new whereas the right muffler is clearly turning brown/golden color (image attached).

Now I understand this discoloration is due to heat, but, why the inconsistency between the right and the left hand side?

The dealer inspected the car and as usual their response was: This is normal and nothing to worry about

Has anyone noticed such discoloration? any thoughts?

Car: 650i 2014 coupe

[E90Fleet]

Yes, they do that.
Different metal parts change color at different rates due to various reasons.

Here is a picture of aremoved 550i exhaust I found on the net showing the typical color changes that happen over time