Lighting only affects tilemaps from one direction.
Found in 4.19 CL# 4033788, 4.20 CL# 4369336, 4.22 CL# 4435744
The tilemap will only be lit in one direction
The tilemap would be lit normally
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-64992 in the post.