tilemap Only half of the light is rendered.

[roumosijidou (肉末四季豆)]

After applying the normal map texture, my tileMap is only rendered by the light at the bottom.
this is tileMap：

sprite paper can work with normal map material.
this is sprite：

[roumosijidou (肉末四季豆)]

Returning the version to 4.18 will solve this problem.