Any environment with volumetric fog enabled will have a light leak which appears through objects.
Found in 4.20 CL# 4369336, 4.21 CL# 4613538, 4.22 CL# 4666322
The volumetric fog affected by the point light on the other side leaks through the wall.
No light leaks would appear through the wall.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-67902 in the post.