Having the same Item in multiple Elements will result in unintended consequences.

[Pluglug]

If the same element item exists (Finger), it will not parse properly and an index error will occur when trying to delete the element.
Implement restrictions after identifying the root cause.

modular_renamer.core.pattern.model - DEBUG: render_name(): Finger_Arm
modular_renamer.core.pattern.model - DEBUG: render_name(): Finger_Finger
modular_renamer.core.service.rename_service - INFO: results:
Finger_Finger -> Finger_Finger
modular_renamer.ui.ui - INFO:
<function MODRENAMER_OT_Rename.execute at 0x000001C279A97E20>: finger 10 REMOVE
modular_renamer.ui.ui - INFO: context.mode: OBJECT
modular_renamer.core.pattern.facade - INFO: PatternFacadeが初期化されました
Traceback (most recent call last):
  File "E:\0187_Pie-Menu-Editor\MyScriptDir\addons\modular_renamer\ui\ui.py", line 104, in execute
    target_item = target_element_pg.get_item_by_idx(self.index)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\0187_Pie-Menu-Editor\MyScriptDir\addons\modular_renamer\preferences.py", line 117, in get_item_by_idx
    return self.items[idx]
           ~~~~~~~~~~^^^^^
IndexError: bpy_prop_collection[index]: index 10 out of range, size 6
繧ｨ繝ｩ繝ｼ: Python: Traceback (most recent call last):
  File "E:\0187_Pie-Menu-Editor\MyScriptDir\addons\modular_renamer\ui\ui.py", line 104, in execute
    target_item = target_element_pg.get_item_by_idx(self.index)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\0187_Pie-Menu-Editor\MyScriptDir\addons\modular_renamer\preferences.py", line 117, in get_item_by_idx
    return self.items[idx]
           ~~~~~~~~~~^^^^^
IndexError: bpy_prop_collection[index]: index 10 out of range, size 6