improve Laravel array validation rule

I am searching for a improvement to this Laravel FormRequest rule set:

protected $stopOnFirstFailure = true;

public function rules()
{
    return [
        'reasons'        => ['required', 'array'],
        'reasons.*.id'   => ['exists:reject_reasons,id'],
        'reasons.*.text' => Rule::forEach(function ($value, $attribute, $data) {
            // get the key from the array attribute
            list(, $key) = explode('.', $attribute);

            $reason = RejectReason::find($this->reasons[$key]['id']);

            return [
                Rule::requiredIf(optional($reason)->with_additional_entry),
                'max:255'
            ];
        }),
    ];
}

The .text element should only be required and checked if the id element exists in the database and the attribute with_additional_entry is true.

Things that could be improved:

• If the id is not in the database the validator does not stop after the reasons.*.id rule, so I have to check for the $reason Object -> optional()
• Get the key of the form array list(, $key) = explode('.', $attribute);

Does anyone have a better solution to this?