If you have an object in the scene that has children, you can delete the object, but that doesn't delete its children. These children are still left behind in some way. This can be reproduced at least with mesh components.
Create an entity with a mesh component with a mesh
Create another entity with a mesh component with a mesh
Move the second entity to be a child of the first entity in the scene
Delete the parent entity
Observe that the child entity's mesh is still drawn
If you have an object in the scene that has children, you can delete the object, but that doesn't delete its children. These children are still left behind in some way. This can be reproduced at least with mesh components.