Looks like WordPress code changed to disable this by default to address some security issue. To bring HTML back, pls make the following code change in the file framework/presentation/slider-manager.php line number 117 and 210 to –
$slide_info = htmlspecialchars_decode (get_post_meta(get_the_ID(), '_slide_info_field', true));
The next update will have this change incorporated into the theme. Thanks for bringing this to my attention.