Thanks to Akuma for sending this one in and giving me a reason to wake up before noon.
The entire thread can be seen over on the PS4 subreddit, detailing what appears to be PS2-style “ghosting”. The graphical effect was used in older PS2 titles like Grand Theft Auto III as a substitute for motion blur, but in 2015, this effect is the sign of a rendering error.
The discussion originally took place on GT Planet (starting on page 509), with a user by the name of SMSRenderTeam confirming that this is indeed a genuine error with the game (skip to page 172 if it doesn’t re-direct properly).
A unique approach to per-object motion blur? Please don’t piss on me and tell me it’s raining.