Why does taking a screenshot of the HTML body using Javascript not show the analysis feedback?

Hello, I am attempting to develop a plugin that develops flashcards of Go positions. The front of the flashcard is a go position. The back of the flashcard will be the same Go position after pressing shift-I (enabling analysis).

While the plugin does in fact toggle analysis via javascript, no screenshot includes the analysis feedback: even though you can see it in the browser, the downloaded image does not contain the analysis markers.

To replicate the problem

Download the source code repo:

Install and use the extension as documented here: