Weird graphical glitch in editor.

I have this weird graphical glitch, it’s made worse by painting trees into my scene, without the trees its absent, and its made more noticeable by turning off my global post processor, so something in that is helping reduce its effect.
Here’s an attached picture

Hi Insideitall,

This is a known issue with Distance Fields AO that should be mostly resolved with 4.8. There may be a few edge cases where this still happens, but largely should be resolved going forward.