I had the same issue. I was using WP 4.5.3 and page-composer.
First you need to find composer-atts.js file. On the line 108, you will find :
return $(“<div/>”).text(rawurldecode(base64_decode(value))).html();
This code needs to be changed by:
return $(“<div/>”).text(rawurldecode(value)).html();
For some reason the content was already encode.
After that you will need to copy and paste the raw html element, delete the old one and update.
Hope it helps.