In reply to mac2net.

There were only a handful, and most of them put out quick fixes inside a few hours. A few themes not on WordPress.org, which include lots of shortcodes (and the kitchen sink) also had problems.

The important takeaway here is to use plugins and themes by developers who are active and can quickly react to change and push updates to their users. Most all of the problems found have been solved already, so all a user has to do is to get the plugin or theme updates, if they're using one that had an issue.

To plugin and theme developers, I would suggest not reinventing the wheel, and while you're at it, trying to reduce complexity. Of the problematic code I've examined, the specific issue isn't one of "bad code" or even using this or that API. It's making shortcodes into something they were never intended or designed for. Users don't need what amounts to a whole programming language built out of shortcodes. If you find yourself building nested shortcodes within nested shortcodes which can contain HTML fragments and if/then options and other seriously arcane levels of complexity... then maybe you should just rethink the problem from the beginning, eh? Just my opinion.