I noticed this earlier this week. I clicked on an image suggestion task from Special:Homepage, and was taken to the article page. The AddImage plugin did not load, I was stuck in "Read" mode. In the browser console, I saw this message:
Your skin is incompatible with VisualEditor. See https://www.mediawiki.org/wiki/Extension:VisualEditor/Skin_requirements for the requirements.
Reloading the page, the AddImage plugin loaded correctly and switched the page into edit mode.