Due to both vercel/vercel#189 (comment) and badges/shields#4878, images on GitHub profiles initially cannot be loaded when, due to missing traffic for a certain period of time (currently around 5 minutes), the Vercel deployment went into "light sleep" mode, since camo.githubusercontent.com signals timeouts after 4 seconds. But the deployment takes around 5 to 7 seconds to wake up and handle the request.

Potential fix:
Move to another web deployment service.