ZDoom

Ambient Occlusion does not render over *3d floor* sectors when using Materials.

https://imgur.com/a/mkF9JFm
Link shows a comparison of the same area, with and without AO.

All sectors share the exact same brightness level of 96(even the control sectors)

Needs a runnable sample.

Here's one with low-res (128x128) textures, and another one with high-res (2048x2048) textures.