GLC Pana sun roof - discolouration of panel between sun roof and windscreen - how is your quality ?

[Teckno]

Hi We have 2016 GLC series with Pana Sun roof - there I’d a filler fixed roof panel between sunroof lip and windscreen.
The filler panel is discolouring along length of the edge.
How are other owners ? Same issue, looks like corroding ?

 

[Teckno]

On closer examination the panel that is discolouring is actually loosing its top coat.
Bit like if you got sunburnt and you loose the top skin layer to peeling. The gloss black revealed a Matt plastic base. Rest of car duco is immaculate, so something wrong with initial application or quality settings.