Strange Indirect Lighting Lines

Hey there!

I’m having some trouble trying to work out why I’m having these strange stark lines showing the different indirect lighting brightness of the walls in my scene. I’ve upped the quality of the lighting substantially and adjusted any other lighting settings to try and work it out to no avail. Lightmaps have been set pretty high for the walls to test out (up to 2048), which seemed to make no difference either, and I’ve never struggled with this issue before, which is leaving me pretty confused.

I’m using one light source, that being the skylight with an HDRI map set at 256 resolution. If anyone has any suggestions, it would be greatly appreciated!!