When exporting still images enscape is generating a pattern in lights. Restarting enscape will fix the issue though sometimes it will just appear in different part of the image. On the 2nd image the pattern is on the interior wall, while on the 3rd image it ended up in the parking lot. Identical scene and settings.
One thing I've found is making sure the resolution is set to "window" prior to launching enscape greatly decreases the chance this happens, vs starting enscape with the custom resolution settings. Using a narrower FOV and more parallel light sources make the pattern more frequent.
These images are on the current preview version 2.4.19023.1003 for Revit, but It also happens on the non-preview build.