Currently, you have two options to show in the feed:
- The excerpt
- The post content
The second option, though, will stop as soon as it encounters a "read more" tag. It would be nice if there was a third option, to include the full post content, even if in the blog you show it with the "read more" tag.
Some background: https://wordpress.org/support/topic/how-can-the-read-more-be-removed-from-the-podcast-feed/