Discoloration on exhaust surround

[AJKOK1]

Noticed the plastic surrounding my exhaust was a bit lighter a few weeks ago and is now looking really ugly. Not sure what could have caused it. Have tried cleaning with WD40, Back to Black etc but it appears to be the actual plastic that has changed colour, and as you can see it goes right under the car above the exhaust. Has anyone else seen this or got any suggestions ??

Thanks in advance Al.

[Trev450]

I would suggest having a word with your OPC about having it replaced under warranty.