It looks like this problem occurs only at pages with (useless) single breadcrumb. Because, there is no (navigation) itemListElement item. Like for example: home page, new products, prices drop ... If you do not need this (useless) single breadcrumb on these pages you can do something like this in your theme file \templates\_partials\breadcrumb.tpl
{if $breadcrumb.count > 1}
<nav data-depth="{$breadcrumb.count}" class="breadcrumb hidden-sm-down">
<ol itemscope itemtype="http://schema.org/BreadcrumbList">
...
</ol>
</nav>
{/if}