link build wrong, missing http prior to //

Since using the widget on my website I have checked the links and the one created by the widget is returning a 301.

the code

<ul><li
id="null-instagram-feed-2" class="widget-container null-instagram-feed"><h2 class="widget-title">our latest picture</h2><ul
class="instagram-pics"><li><ul><li
id="null-instagram-feed-2" class="widget-container null-instagram-feed"><h2 class="widget-title">our latest picture</h2><ul
class="instagram-pics"><li><a
href="//instagram.com/p/xy28YTxunD/" target="_blank"><img
src="//scontent-a.cdninstagram.com/hphotos-xfa1/t51.2885-15/s150x150/e15/10899305_645662328878510_1742340259_n.jpg" alt="Lovely day..." title="Lovely day..."/></a></li></ul></li></ul><ul><li
id="text-10" class="widget-container widget_text"><img
src="//scontent-a.cdninstagram.com/hphotos-xfa1/t51.2885-15/s150x150/e15/10899305_645662328878510_1742340259_n.jpg" alt="Lovely day..." title="Lovely day..."/></a></li></ul></li></ul><ul>

shows <a href="//instagram.com/p/xy28YTxunD/" target="_blank"> which translates into a link precluded with the sites domain as the http is missing prior to the //

https://www.ads-software.com/plugins/wp-instagram-widget/