Content:Encoded not in JSON Response

I am retrieving data from this RSS feed:https://www.merlot.org/merlot/materials.rss?hasAwards=false&hasComments=false&hasCourses=false&filterTypesOpen=false&keywords=EarlyProgress&dateRange=0&hasEtextReviews=false&isLeadershipLibrary=false&hasCollections=false&filterOtherOpen=false&isContentBuilder=false&filterSubjectsOpen=true&hasAccessibilityForm=false&hasPeerReviews=false&fromAdvancedSearch=true&hasAssignments=false&filterPartnerAffiliationsOpen=true&hasRatings=false&hasSercActivitySheets=false&days=7&filterMobileOpen=false&hasEditorReviews=false&page=1
I want to iterate through all of the items and parse the content.  I am able to get every element except content:encoded.
If I console log the ajax response and then console log one of the item elements, I see them all except for content:encoded.  Example:
0:
author: "Amir Karimi The University of Texas at San Antonio"
link: "https://www.merlot.org/merlot/viewMaterial.htm?id=1138036"
pubDate: "Tue, 15 Mar 2016 14:45:55 GMT"
title: "Factors Influencing Student Graduation Rates"

Here is my code using an ajax request, assuming json return type:
$.getJSON(url).then( function(response) {buildFeed(response.data['channel']['item']);});

function buildFeed(data) {  
    let feed = "";

    console.log(data);

    //for each row of data
    $.each(data, function(key, value) {

feed = feed + '<div className="feed-item">';
feed = feed + '<div><a href="' + value.link + '" target="_blank">' + value.title + '</a></div>';
feed = feed + '<div></div>';
feed = feed + '<div>' + value.pubDate + '</div>';
feed = feed + '<div>Author: ' + value.author + '</div>';
feed = feed + '<hr/>';
feed = feed + '</div>';

    }); 

    //Load feed
    $feed.html(feed);
}

I also tried making an ajax request with an xml request type, but received a parse error.  Code below:
url: appURL + '/merlot-feeds/feed/earning-jr-status/',
dataType: "xml",
success: function(xml) {

//it never gets here
console.log('success');
console.log(xml);

},
error: function(xhr, status) {

//The request always returns an error
console.log('error');
console.log(xhr);
console.log(status);    //result is "parserror"
console.log(xhr.responseText);

}
    }); 

The above ajax call fails, and when I console log the status is reads "parsererror".  However, if I console log the response text I get the complete response object.
Is the following asusmption correct: the source xml is not set up correctly and this is why it is throwing a parseerror error?  How can I resolve this issue and extract the encoded content?

I was able to get the content as an Atom feed instead of an RSS feed, which switched the tag from <content:encoded> to <summary>, and now I can use the first method just fine.  Not really an answer and doesn't resolve the root cause, but hey, it's working now.