Paypal App - Product form

When I view source code of the product page I am seeing this

<perch:form template="" template="/templates/shop/product.html" id="_xclick" method="post" action="https://www.paypal.com/cgi-bin/webscr" class="cart">

Notice the template=""

What could be causing this?

Product.html is this

<div class="row">
<div class="col-md-6">

<div class="owl-carousel" data-plugin-options='{"items": 1}'>
    <div>
        <div class="thumbnail">
            <img alt="<perch:shop id="productTitle" />" class="img-responsive img-rounded" src="<perch:shop id="productImage" label="Image" type="image" width="555" height="555" crop="true" bucket="shop" />">
        </div>
    </div>
</div>
</div>


<div class="col-md-6">
    <div class="summary entry-summary">

        <h1 class="mb-none"><strong><perch:shop id="productTitle" /></strong></h1>

        <p class="price"><span class="amount">&pound;<perch:shop id="productPrice" /></span></p>
        <p>Description</p>
        <perch:shop id="productDescHTML" type="textarea" editor="ckeditor" html="true" size="m" />                      

        <perch:form id="_xclick" method="post" action="https://www.paypal.com/cgi-bin/webscr" class="cart">
        <perch:input type="hidden" name="business" value="<perch:setting id="perch_shop_paypal_email" />" />
        <perch:input type="hidden" name="currency_code" value="GBP" />
        <perch:input type="hidden" name="cmd" value="_cart" />

        <div class="quantity">
            <input type="button" class="minus" value="-">
            <input type="text" class="input-text qty text" title="Qty" value="1" name="add" min="1" step="1">
            <input type="button" class="plus" value="+">
        </div>

        <perch:if exists="productOptions_html"><perch:shop id="productOptions_html" encode="false" type="hidden" /></perch:if>

        <perch:input type="hidden" name="add" value="1" />     
        <perch:input type="hidden" name="item_name" value="<perch:shop id="productTitle" />" />
        <perch:input type="hidden" name="item_number" value="<perch:shop id="productCode" />" />
        <perch:input type="hidden" name="amount" value="<perch:shop id="productPrice" />" />


        <button class="btn btn-primary btn-icon"><perch:input type="submit" name="add" value="Add to cart" /> Add to cart</button>
        </form>

        <!--<div class="product_meta">
            <span class="posted_in">Categories: <a rel="tag" href="#">Accessories</a>, <a rel="tag" href="#">Bags</a>.</span> 
            </div>-->

        </div>
    </div>
</div>