I've a multi-line text metafield linked to my product page as a dynamic source in a richtext field (the only one that supports it).
If I include some simple HTML tag in the metafield value in the product, they are converted as text and shown in the page.
If I add to the richtext some other text and use the interface to make it italic it's displayed correctly. I think that is a bug because there is no way to include some formatting in a metafield multi-line text using the customizer.
I've tried to use a single-line text metafield as a dynamic source of a text field and putted some HTML tags in it and it works like a charm, in a field that is supposed to strip that.