This often happens when the scene lighting isn't strong enough and or due to the roughness of the material.
Reflective surfaces seems to suffer the most. No real workaround apart from adjusting the materials and or making them slightly emissive.
It is as known 'limitation' and they are working on resolving it.
this known "limitation" would occur with high reflectivity but in the case of the black matte wall I don't get it. Of course reflective surfaces suffers the most. The scene is not auto exposed and has a HDR