Operating system: Ubuntu 18.04
Graphics card: GTX 1080 Ti
Broken: 2.81 2019-12-05
Short description of error
I'm using adaptive subdivision for micro-displacements to turn a surface mesh into a thick scarf with yarn geometry. In some of my animation's frames I have found spikes in the rendering such as here:
It seems to be deterministic in that I can reproduce it for a single frame of the animation; I attached the blend file for a minimal example of a single frame with the issue.
This issue does not happen in the progressive viewport render. Also, since the ao-map that I'm using to drive the displacement does not change over time but this happens only in some frames, it is likely not related to the displacement map but more to the mesh and the adaptive subdivisions.
Exact steps for others to reproduce the error
Open the blend file and press F12 to render