Hello,

I could imagine 2 reasons: Shadow setting or too much light.

Check the shadows, if the min bias is too high, light shines "through" the objects. (Don't set it too low, what can also cause problems). The default in my installation is 0.8 meters. Reduce that to something between 5 and 10 cm (or 2 to 4 inch if you use that scale).  Use raytraced shadows instead of depth mapped shadows.

For the second attempt, reduce the light intensity to 25% of their current value (maybe 50% for the main light (sun)). If too many (or too strong) light sources shine on the shadowed areas, they might "erase" the shadow by providing too much light. If everything fails, disable (uncheck "on") all light sources except the sun, and then do iteratively enable single light sources again, until you find the "culprit".

 

Best regards,

   Michael