Building Light Stuck/Taking far too long.

After switching to 4.13 light building even with simple default settings on preview quality is taking an absurdly long time. I am used to using higher settings, with more objects and lights and it has never taken close to as long as it is now. It is hanging at 0% for a long time, then 66% for an extremely long time, and 90% for as long as I will let it sit.