Stationary Spot Lights in Forward Rendering cause artifacts when lighting transluceny set to Volumetric PerVertex NonDirectional. When the camera is moved around the object, the lit vertices flicker. Stationary Point Lights however function as expected and do not flicker.
Found in 4.21 CL# 4753647, 4.22 CL# 6574378, 4.23 CL# 6925347
The Sphere will flicker and artifact
The sphere would be lit appropriately as it is with other light sources
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-76293 in the post.