Panamera window trim

[Nick981]

One of the shiny black pieces of window trim between the drivers and rear passengers door windows has started getting a silvery crazed finish on my 2019 Panamera Sport Turismo. My dealer says I must have accidentally got some chemical on it and therefore it’s not a warranty issue, but I think it’s odd that the piece next to it is unaffected and I believe that it’s down to a part that is deteriorating and therefore should be replaced under warranty as it’s not fit for purpose. I’m just wondering if anyone else has experienced anything similar?
(I’ve been quoted over £1k to replace what is essentially a plastic strip!)