Early in my ownership (more than 2 years ago!) I briefly mentioned that the indicators on the North American 4C are quite strange, and I finally remembered to snap a video:
It has both a ring of LEDs and a central filament bulb. If you thought perhaps there’s some clever functional division with the brake lights, you would be wrong—they all light up in unison for braking.
So for turns or hazards, you have a really odd visual effect of both the LEDs toggling instantly and the bulbs illuminating and dimming with a delay. Super, super weird.
The only explanation is that somehow neither the bulb nor the LED ring can meet US DOT specifications on their own (probably that weird surface area requirement), so they had to be mashed together.
Also, in the RoW car the central bulb is amber and not red, because it’s not used for the brake lights.
The taillights are a larger outer ring and not shared.