Invalid description

[FarmaanElahi]

For this feed : http://feeds.serialpodcast.org/serialpodcast
Whenever I query for feed.description it returns itunes:subtitle results

Snippet from the rss feed:

<description>Serial is a podcast from the creators of This American Life, hosted by Sarah Koenig. Serial unfolds one story - a true story - over the course of a whole season. The show follows the plot and characters wherever they lead, through many surprising twists and turns. Sarah won't know what happens at the end of the story until she gets there, not long before you get there with her. Each week she'll bring you the latest chapter, so it's important to listen in, starting with Episode 1. New episodes are released on Thursday mornings.</description>
<language>en</language>
<copyright>Copyright 2018 Serial Podcast</copyright>
<itunes:author>This American Life</itunes:author>
<itunes:subtitle>A podcast from the creators of This American Life</itunes:subtitle>

Ideally it should return the description since this exists but it return tunes:subtitle content