Multiple Variant Input require item code

I’m a student and new to erpnext and frappe framework
While I learn about inventory management and learn to make variation from template item I got this bug

from inspect element > network

{"exc_type":"ValidationError","exception":"frappe.exceptions.ValidationError: Item Code is required","exc":"[\"Traceback (most recent call last):\\n  File \\\"apps/frappe/frappe/\\\", line 69, in application\\n    response = frappe.api.handle()\\n  File \\\"apps/frappe/frappe/\\\", line 54, in handle\\n    return frappe.handler.handle()\\n  File \\\"apps/frappe/frappe/\\\", line 45, in handle\\n    data = execute_cmd(cmd)\\n  File \\\"apps/frappe/frappe/\\\", line 83, in execute_cmd\\n    return, **frappe.form_dict)\\n  File \\\"apps/frappe/frappe/\\\", line 1598, in call\\n    return fn(*args, **newargs)\\n  File \\\"apps/erpnext/erpnext/controllers/\\\", line 226, in enqueue_multiple_variant_creation\\n    return create_multiple_variants(item, args)\\n  File \\\"apps/erpnext/erpnext/controllers/\\\", line 247, in create_multiple_variants\\n\\n  File \\\"apps/frappe/frappe/model/\\\", line 301, in save\\n    return self._save(*args, **kwargs)\\n  File \\\"apps/frappe/frappe/model/\\\", line 323, in _save\\n    return self.insert()\\n  File \\\"apps/frappe/frappe/model/\\\", line 250, in insert\\n    self.set_new_name(set_name=set_name, set_child_names=set_child_names)\\n  File \\\"apps/frappe/frappe/model/\\\", line 446, in set_new_name\\n    set_new_name(self)\\n  File \\\"apps/frappe/frappe/model/\\\", line 172, in set_new_name\\n    frappe.throw(_(\\\"{0} is required\\\").format(doc.meta.get_label(fieldname)))\\n  File \\\"apps/frappe/frappe/\\\", line 523, in throw\\n    msgprint(\\n  File \\\"apps/frappe/frappe/\\\", line 491, in msgprint\\n    _raise_exception()\\n  File \\\"apps/frappe/frappe/\\\", line 443, in _raise_exception\\n    raise raise_exception(msg)\\nfrappe.exceptions.ValidationError: Item Code is required\\n\"]","_server_messages":"[\"{\\\"message\\\": \\\"Item Code is required\\\", \\\"title\\\": \\\"Message\\\", \\\"indicator\\\": \\\"red\\\", \\\"raise_exception\\\": 1}\"]"}

the args that sent to controller seems not quite right

args: {"<span+class=\"input-area\"><input+type=\"checkbox\"+autocomplete=\"off\"+class=\"input-with-feedback\"+data-fieldtype=\"Check\"+data-fieldname=\"15\"+placeholder=\"\"></span>\n\t\t\t\t\t<span+class=\"disp-area\"+style=\"display:+none;\"><input+type=\"checkbox\"+disabled=\"\"+class=\"disabled-selected\"></span>\n\t\t\t\t\t<span+class=\"label-area\">15</span>":["15","24"]}

then i check that variable is treated as json, but it’s html (as i shown before)

i add line 226 to check the output and this is the result

I assume there’s error when naming the variant from controller but i don’t know how to fix it, anyone have the same problem with me and already fix this bug? or is it just a beginner mistakes with simple solution :sweat_smile: