使用Jira中的REST api修改自定义字段名称后，CustomFieldManager没有获得自定义字段

我正在使用JIRA中的REST API更改自定义字段名称。
它正在成功更改自定义字段名称。
但是，当我尝试将自定义文件提交到代码中时，结果为null。

I'm changing the custom field name using the REST api in JIRA. It is changing the custom field name suceessfully. But when I tried to get the custom filed in the code, I'm getting null as the result.

String modByWhomCustomFieldName = pluginConfigService.getMUFCustomFieldName();
    System.out.println("+++++++++++++++++++In flagCustomField() modByWhomCustomFieldName is:"+modByWhomCustomFieldName);

    //CustomField modByWhomCustomField = cfManager.getCustomFieldObjectByName("Description Changed By");
    CustomField modByWhomCustomField = cfManager.getCustomFieldObjectByName(modByWhomCustomFieldName);
    if(modByWhomCustomField != null) {
        System.out.println("++++++++++++++ "+modByWhomCustomField.getDescription());
    }

在上面，它没有进入if条件。

In the above it is not entering into the if conditon.

从这里编辑。
每当用户更改问题描述时，我都会显示该用户。为此，我创建了一个类型为 UserCFType的自定义字段。它显示的是修改说明的用户。但是对于用户admin，它将显示admin（admin）。我只希望 admin而不是 admin（admin）。

Edited from here. Whenever user changed the description of an issue, I'm displaying that user. For this I have created one custom field of type "UserCFType" . It is displaying the user who modified the description. But for user admin, it is displaying admin(admin) . I just want "admin" only not "admin(admin)".

Object modByWhomCustomFieldOldValue = issue.getCustomFieldValue(modByWhomCustomField);
        Object modByWhomCustomFieldNewValue = user;
        System.out.println("+++++++++++++++++++In flagCustomField() current user is:"+modByWhomCustomFieldNewValue.toString());

        ModifiedValue<Object> modifVal2 = new ModifiedValue<>(modByWhomCustomFieldOldValue, modByWhomCustomFieldNewValue);
        modByWhomCustomField.updateValue(null, issue, modifVal2, changeHolder);

上面是该代码。