In the website editor, if the user sets an alt tag on an image the generated HTML for the page includes that alt tag in the surrounding div instead of on the img element. See screenshot.
This is a strange place for the alt info and causes Lighthouse to throw a warning indicating that no alt text is set on any images on the page.
All methods for setting alt text for an images in the page editor seem to show this same alt text behavior.
This is a significant SEO issue and will hopefully be an easy fix.