The light flashes seemed to happen as I was walking around. I think it might be related to the line of sight? This was not the post DD version though.
Viewing post in Plunderground jam comments
If you played the original upload, the new version should fix quite a bit. The lighting flashes "should" be gone (they seemed to appear for AMD GPUs and only in dungeons due to them having both fog AND volumetric fog enabled, the latter being gone in the new version), and the enemies are also more responsive and active compared to the older version. Loading times are also shorter.