GPU Lightmapper creates sparkly mess (only in some scenes though?)

Anyone know what could be causing this? CPU Lightmapper works fine but takes 10 million billion Carl Sagan years. The settings are the exact same as I use in a different scene, where the issue does not appaer. So I’m quite baffled. Did I forget to install the ‘Make GPU Lightmapper work consistently’ package? And what packages does that pacakage depend on or conflict with? Do I need to also get the 'Solve package conflicts when installing the ‘Make GPU Lightmapper work consistently’-package package? Questions upon questions, the joys of working with Unity.

Which Unity version are you using? Keep in mind that GPU PLM is still in a preview state, so issues are expected.

What you are seeing here are NaNs. Those could be caused by a multitude of reasons. Have you tried looking through a pinned post on how to manage such artifacts?