HTML code appears after marking a lesson as completed

Hi,
I have created a course with several lessons on my website.
I marked the first lesson as “Completed” with the top right button inside the lesson. But when O go back to the course lesson list, my first lesson appears in the list with HTML tags, like this:
Name_of_the_lesson<span class=”dtlms-completed”><span class=”fas fa-check”></span></span>

Apparently it should show the check icon, but it only shows the HTML code of it.

Jean Boudoy