So I’m just adding my two cents here but, I can’t tell the difference, and I’m still getting the error, so fingers crossed I’m hoping that they need to update the Testing Tool
/*THIS IS MINE*/
<span prefix="v: https://rdf.data-vocabulary.org/#">
<span typeof="v:Breadcrumb">
<a href="https://www.petplanethealth.com/store-locations/alberta/" rel="v:url">Alberta</a> \
<span rel="v:child" typeof="v:Breadcrumb">
<a href="https://www.petplanethealth.com/stores/crowfoot-corner/" rel="v:url">
Crowfoot Corner
</a>
</span>
</span>
</span>
/* THIS IS FROM GOOGLE */
https://developers.google.com/structured-data/breadcrumbs
<div xmlns:v="https://rdf.data-vocabulary.org/#">
<span typeof="v:Breadcrumb">
<a href="https://www.example.com/books" rel="v:url">
Books
</a> ?
<span rel="v:child" typeof="v:Breadcrumb">
<a href="https://www.example.com/books/fiction" rel="v:url">
Fiction
</a> ?
<span rel="v:child" typeof="v:Breadcrumb">
<a href="https://www.example.com/books/fiction/horror" rel="v:url">
Horror
</a> ?
</span>
</span>
</span>
</div>