4-27 Mobile Shadow Problem

Currently, there is an issue in which shadows are not rendered in Moveable Light in the absence of a lightmap at the level in the mobile rendering environment in Unreal 4.27.1 ES3.1-Vulkan.
Although this phenomenon is solved when static lighting is disabled or rendering is replaced by Deferred rendering, due to the spciality of the project, the level at which static lighting is required.
The problem continues as only the level required for the moveable light is separated.
Is this part has been changed to an unreal policy or a simple error?
And if it’s an error, I wonder if the hotfix plan in the future includes a roadmap for resolving this error.