Caused by rB4c3d51326efa: LibOverride: Refactor 'make override' 3DView operator.
Custom bone shapes are actually getting an override now [which is
unwanted].
For custom bone shapes, the tag for making an Override is removed in
lib_override_linked_group_tag after
lib_override_linked_group_tag_recursive.
But in above commit, an additional
make_override_hierarchy_recursive_tag (now
lib_override_hierarchy_dependencies_recursive_tag) was introduced that
could tag the custom bone shapes again afterwards.
Not 100% sure where the best place for tag removal now is, but propose
to move it to lib_override_library_create_do (after
lib_override_linked_group_tag /
lib_override_hierarchy_dependencies_recursive_tag have done their
thing).