I've got a couple of sites that are using Dynamik child theme, and that are having an issue with the Easy Table of Contents plugin on PHP 7+, but only when the Dynamik theme is activated.
Here's what's running on my sites:
PHP Version: 7.1.27
WordPress Version: 5.1.1
Genesis Version: 2.9.1
Dynamik Version: 2.5.3
Font Awesome Version: 4.7.0
So what is happening is that when the Easy Table of Contents plugin is activated, on pages where the TOC appears all sorts of weird things happen.
The styling looks off and doesn't quite look right, Headings (H2, H3, etc) on the page are duplicated/showing up more than once, although one of the headings is usually cut off. An example:
If I deactivate all plugins except the TOC one, it doesn't help, the problem persists.
If I downgrade to PHP 5.6, the problem goes away.
If I stay on PHP 7.1, and change the theme from Dynamik to the stock 2019 theme, the issue goes away and it functions correctly.
So I'm not sure what's happening here. I know of others who are on PHP 7 who are using this plugin without problems (using other themes), and the only thing that seems to make the issue go away is if I stop using the dynamik theme which i don't want to do.
Not sure if anyone can figure out what's causing this to happen - if it's something in Dynamik, Dynamik + plugin or something else?
You can view the issue on the live site here, a page with more than 4 headings and a table of content being inserted: