too much noise reduction

I just thought this was funny. This person is riding a bicycle. Can you see it?
In the video the bike is faintly visible in earlier and later frames, but this was the event keyframe that I saw first.
I have several external IR lights, but I am not using the camera's internal IR at all, to avoid insect & spider problems.

Camera is 2MP Dahua Starlight IPC-HDW5231R-Z
Gain Priority, Gain 0..30, 3D NR ON, Grade setting 8/100 (nearly off)
Software 2.460.0000.1.R, Build Date: 2016-10-25

Just for comparison, the same bicyclist from a $65 Dahua IPC-HDW4431C-A retrofit with a 16mm lens, directly in the beam of my external IR spotlight. I think the bike frame is black and I don't see any reflectors.

I did not know Zombies could ride bikes.