MJML issue #1736: API sometimes returns invalid JSON

mjml-api-invalid-json-request

{"mjml":"<mjml><mj-head><mj-preview>%FIRSTNAME%, are you and %SPOUSE_FIRSTNAME% today's giveaway winners?<\/mj-preview><mj-attributes><mj-all font-family=\"Arial, Helvetica, sans-serif\" align=\"center\" \/><mj-button background-color=\"#55aaa4\" border=\"1px solid #499e98\" font-size=\"18px\" \/><mj-text color=\"#555555\" font-size=\"16px\" \/><mj-class name=\"footer-text\" align=\"center\" color=\"#AAAAAA\" font-size=\"11px\" line-height=\"13px\" \/><\/mj-attributes><\/mj-head>  <mj-body><mj-section padding=\"0\"><mj-column><mj-image src=\"https:\/\/weddingvibe.com\/images\/email\/wv\/WV-Winner-Announced-header.jpg\" alt=\"WeddingVibe Giveaway Winner Announced\" title=\"WeddingVibe Giveaway Winner Announced\" align=\"center\" width=\"600px\" padding=\"10px 0\"><\/mj-image><\/mj-column><\/mj-section><mj-section padding-top=\"0\"><mj-column><mj-text>Check our Giveaway Winners page to see if you are the winner of...<\/mj-text><mj-text font-size=\"24px\" padding-bottom=\"5px\">Wedding Speech Help<\/mj-text><mj-text padding-top=\"5px\">By: <a href=\"https:\/\/laughstaff.com\/best-man-maid-of-honor-speeches-written-by-comedians\/\">Laugh Staff<\/a><\/mj-text><mj-image src=\"https:\/\/weddingvibe.com\/wp-content\/uploads\/2019\/03\/laugh-staff-giveaway-360x240.jpg\" href=\"https:\/\/laughstaff.com\/best-man-maid-of-honor-speeches-written-by-comedians\/\" align=\"center\" width=\"360px\"><\/mj-image><\/mj-column><\/mj-section><mj-section background-color=\"#e2a5c3\" padding=\"15px 0 10px 0\"><mj-column><mj-text font-size=\"24px\" padding=\"0 0 5px 0\">Exclusive Offer for %FIRSTNAME% and %SPOUSE_FIRSTNAME%<\/mj-text><mj-text padding=\"0\">Courtesy of Laugh Staff<\/mj-text><\/mj-column><\/mj-section><mj-section background-color=\"#ffedf6\" border=\"1px solid #e2a5c3\" padding=\"10px 0\"><mj-column><mj-text font-weight=\"700\">Get 10% Off Your Wedding Speeches with Code WEDDINGVIBE<\/mj-text><mj-button background-color=\"#ac3471\" border=\"1px solid #7d2652\" href=\"https:\/\/laughstaff.com\/best-man-maid-of-honor-speeches-written-by-comedians\/\">Get Offer<\/mj-button><\/mj-column><\/mj-section><mj-section><mj-column><mj-button href=\"https:\/\/weddingvibe.com\/giveaway-winners\/\">See Giveaway Winners<\/mj-button><mj-button background-color=\"#eef6f6\" border=\"1px solid #55aaa4\" color=\"#55aaa4\" href=\"https:\/\/weddingvibe.com\/giveaway\/\">Enter New Giveaways<\/mj-button><\/mj-column><\/mj-section><mj-section padding=\"0\"><mj-column><mj-spacer height=\"30px\" \/><\/mj-column><\/mj-section><mj-section background-color=\"#575757\" padding=\"10px 0\"><mj-column><mj-text mj-class=\"footer-text\" font-size=\"14px\" line-height=\"16px\" padding-bottom=\"0\"><strong>Wedding Details for %FIRSTNAME% &amp; %SPOUSE_FIRSTNAME%<\/strong><br \/>Date: %WEDDING_DATE%<br \/>Location: %WEDDING_CITY%, %WEDDING_STATE%<\/mj-text><mj-text mj-class=\"footer-text\" padding-top=\"0\"><a style=\"color:#AAAAAA; text-decoration:underline;\" href=\"https:\/\/weddingvibe.com\/account\/\" target=\"_blank\" rel=\"noopener\">Update your wedding details<\/a><\/mj-text><mj-text mj-class=\"footer-text\">Trouble viewing this email? <a style=\"color:#AAAAAA; text-decoration:underline;\" href=\"%WEBCOPY%\" target=\"_blank\" rel=\"noopener\">View it as a web page<\/a><\/mj-text><mj-text mj-class=\"footer-text\">WeddingVibe is not the sponsor of this offer, does not make any endorsements or guarantees, and expressly disclaims any responsibility or liability with respect thereto, including without limitation, any offer herein or materials provided in connection therewith for any loss or damage of any sort incurred as the result of any such dealings or as the result of third-party promotions.<\/mj-text><mj-text mj-class=\"footer-text\">You received this email because you created an account at WeddingVibe.com.<br \/><a style=\"color:#AAAAAA; text-decoration:underline;\" href=\"%UNSUBSCRIBELINK%\" target=\"_blank\" rel=\"noopener\">UNSUBSCRIBE<\/a> from <strong>Giveaway Winner Announcement emails<\/strong>.<br \/>If you no longer want to receive any emails from WeddingVibe.com, <a style=\"color:#AAAAAA; text-decoration:underline;\" href=\"%UNSUBSCRIBELINK%&ALL\" target=\"_blank\" rel=\"noopener\">click here<\/a>.<\/mj-text><mj-text mj-class=\"footer-text\">\u00a9 2019. All rights reserved. %SENDER-INFO-SINGLELINE%<\/mj-text><mj-image src=\"https:\/\/weddingvibe.com\/images\/email\/wv\/WV-logo-grey.png\" alt=\"WeddingVibe.com\" title=\"WeddingVibe.com\" align=\"center\" width=\"191px\" padding-top=\"0\"><\/mj-image><\/mj-column><\/mj-section>  <\/mj-body><\/mjml>"}