Having been alerted to the problem by Chris, another GP owner, I find that like his GP, my cars rear spoiler fixing screws are rusting and looking rather ugly!
This issue is not happening for all owners – I suspect it’s related to weather conditions and perhaps whether or not the car is garaged (GP0203 is not) … I’ll be chatting to my dealership to see what they think about it …
M&I / GBMINI 
not a spot on GP0154, guess the TX weather helps but GP1717 has one that is starting and maybe spending the winter in her bubble helps.
If you have them replaced you may want them to spray them black before putting them back on to help prevent it from happening again also help disguise them a bit.
Next week I’ll take GP1717 bolts off and soak them in a rust remover/anodizer that Detailing Dynamics has that I used on a few of the classics bolt that made them like new. In the classics case they appear to be made of the same material and most of her bolts were surface level and easily cleaned up.