There is an issue where Point lights with source length building static lighting in the incorrect direction, the axis in which the light to be built seem to conflict with the preview build. This issue does not occur unless the light is set to static. This issue appears to be a regression.
4.18.3 CL - 3832480 - Issue does not occur
4.19.0 CL - 3944462 - Issue occurs
4.20.0 CL - 3952118 - Issue occurs
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-56344 in the post.