Apply plug-in in 2 environment, but only one work.

Thanks for your support.

We apply Repeatable Fields plug-in into 2 environment with same code in CF7,
one successfully create repeat specify column but another is failed.

Below is the successful one, when need new repeated group, just press button “+”:

Below is the failed one, it original exist button “-” and “+”, and it have no response after click it:

And I found the failed one cannot generate “__$index”:

Below is the [field_group] code we use at both environment:

[field_group students id="students-groups" tabindex:1]
        <div class="container">
          <div class="row">
            <div class="columns one-third">
              <div class="field"><label>中文姓名<em>*</em></label>[text* student_nameZHT]
                <p class="info-tip"></p>
              </div>
            </div>
            <div class="columns one-third offset-one">
              <div class="field"><label>英文姓名<em>*</em></label>[text* student_nameUS]
                <p class="info-tip"></p>
              </div>
            </div>
          </div>
        </div>
        <div class="container">
          <div class="row">
            <div class="columns one-third">
              <div class="field"><label>性別<em>*</em></label>[select* student_gender include_blank "男" "女"]
                <p class="info-tip"></p>
              </div>
            </div>
            <div class="columns one-third offset-one">
              <div class="field"><label>年級<em>*</em></label>[select* student_class include_blank "初一" "初二" "初三" "高一" "高二" "高三" "教師"]
                <p class="info-tip"></p>
              </div>
            </div>
          </div>
        </div>
[/field_group]

We’ve no idea which setting cause 2 environment different result,
the plug-in version are same in both environment.

Best Regards,
Kage