I recently came across this odd issue related to shadows: it basically has this darkening effect on regions beneath MeshParts, as if both the old shadow and the new shadows are combined.
The bug happens in Studio and the live player.
I’m not sure about any other detail sadly, but I hope this was sufficient. 
Reproduction place:
Thanks for the report! We’ve filed this internally and we’ll follow up here when we have an update for you.
Apologies for the confusion here, but this feature is functioning as intended. If you have any further bug reports, please create a new topic for us to look into.
Ah okay! Sorry, I didn’t know. 
Hopefully it didn’t take too much time!
What exactly is causing the odd shadows, and how can I resolve them? 
You can play with the collision fidelity to change the amount of voxel-based shadows being mixed in.
On the flip side, I use this effect intentionally in my games, it acts as a sort of global illumination.
