Little help for a little error in this awesome plugin.

Today, I have shifted to from the previous amazing FBIA plugin called “WordPress Instant Articles by allfacebook.de” to your plugin. Everything looks amazing.

But there is just one content error that I noticing under the development article.

It appears something like this:

It says ” Unsupported Class: The <figure> element has an unsupported class value in the class=op- tag. For more information on the class values supported in <figure> element you’re using, refer to the Format Reference of the Instant Articles documentation.”

How to avoid this error?

Thank