使用自定义错误消息的 required_with 没有效果

PHP代码

Validator::make(
    [
        "title" => [1 => "1", 2 => null],
        "body" => [1 => null,2 => "<p>2</p>"],
    ],
    [
        "title.1" => "required_with:body.1|nullable|string|max:255",
        "body.1" => "required_with:title.1|nullable|string",
        "title.2" => "required_with:body.2|nullable|string|max:255",
        "body.2" => "required_with:title.2|nullable|string",
    ],
    [
        "title.1.required_with:body.1" => "The 中文 (简体) title is required when content 中文 (简体) is present.",
        "body.1.required_with:title.1" => "The 中文 (简体) content is required when title 中文 (简体) is present.",
        "title.2.required_with:body.2" => "The 中文 (繁體) title is required when content 中文 (繁體) is present.",
        "body.2.required_with:title.2" => "The 中文 (繁體) content is required when title 中文 (繁體) is present.",
    ]
);

验证结果得到

The body.1 field is required when title.1 is present.
The title.2 field is required when body.2 is present.

而不是

The 中文 (简体) content is required when title 中文 (简体) is present.
The 中文 (繁體) title is required when content 中文 (繁體) is present.

然后我在 Illuminate\Validation\Concerns\FormatsMessages 的 getFromLocalArray() 发现

"getFromLocalArray -> $keys"
array:2 [▼
  0 => "body.1.required_with"
  1 => "required_with"
]

"getFromLocalArray -> $this->customMessages"
array:4 [▼
  "title.1.required_with:body.1" => "The 中文 (简体) title is required when content 中文 (简体) is present."
  "body.1.required_with:title.1" => "The 中文 (简体) content is required when title 中文 (简体) is present."
  "title.2.required_with:body.2" => "The 中文 (繁體) title is required when content 中文 (繁體) is present."
  "body.2.required_with:title.2" => "The 中文 (繁體) content is required when title 中文 (繁體) is present."
]

keys 和 customMessages 的键名对不上，请问我的自定义验证规则有什么写错了吗?