We just moved the post over from Wordpress on April 23rd. We haven’t made any changes to the blog’s theme as of yet, we’re still working with the “Default blog post” template.
If that works then may want to tune the existing rule in the themes style.css around line 2451 that causes this display behavior keeping in mind that would affect the entire site.
img,
audio,
video {
height: auto;
max-width: 100%;
}
If you are looking for a way to manage this with an easy to use app check out Listen Now! The app started as a text to speech tool for blog posts and now supports audio for blog posts and most pages on Shopify. Pretty nifty.