I can’t reproduce this reliably. But sometimes, when I rename a guide, I end up with “leg_L0_L0_root” instead of "leg_L0_root"
Only the root has the incorrect name. All the children are fine.
I think it happens when I’m renaming the guide in the settings UI. But not always. Possibly when an old guide used to have the same name. For example, I am deleting a leg_2jnt_01 module and replacing it with a leg_3jnt_01 module with the same name.
When I go to build the rig, I get an error because it expects to find that guide root:
Object missing : leg_L0_root # Error: line 1: root # Traceback (most recent call last): ... not relevant error messages here
To fix it, I have to rename the guide from leg_L0_L0_root, back to leg_L0_root manually.