The issue was that when applying the keyingsets
`Whole Character` and `LocRotScale & Custom Properties` the
enum property of a rigify rig was not keyed.
The reason it was not keyed was just because
it was not specified in the compatible types in the keying set.
The fix is to just add `bpy.types.EnumProperty` to the list.
Pull Request: https://projects.blender.org/blender/blender/pulls/122377
9dcc63b76c