This is a known issue and is likely a bug in the original HTML2Canvas library that this plugin is built on. You can read a bit more about this library here: https://github.com/niklasvh/html2canvas Relevant examples: https://github.com/niklasvh/html2canvas/issues/2958 / https://github.com/niklasvh/html2canvas/issues/2937 While the screenshots aren't perfect, they should be sufficient for most cases where you're just trying to share the settings on a page.
Working on it. Next version.
Hopefully in a future version. = The screenshot is not saving. Is there a debugging feature to see what might be wrong here? Not yet, but hopefully in a future version.
Please go to the plugin's WordPress.org support forum and let me know.
It's very possible, or even likely, that something's not right; I can only do so much testing and it's impossible to test the plugin with every single setup out there, so there's a good chance that it will have some issues. Please report any bugs on the plugin's WordPress.org support forum.