New Page Not Added to Thumbnail-Navigation Display

I’ve been using the following tag for years without issue:
[autonav display="images" pics_only="1" size=150x150]
I added a new sub-page for the first time this year, and that page’s thumbnail will not show up in the list…

Here are the things I tried to get it to work:

• Verified that the new page was correctly added to the page hierarchy: it was… there are other plugins that help create navigation links, and the new page was detected and used by these other plugins without issue.
• Verified that the full-sized image name didn’t duplicate the thumbnail naming convention 150×150, etc.
• Changed the type of display to “list” to see if there was an issue with the image: no change; the page did not display in the list.
• Looked through all of the HTML & WordPress Metadata to see if there was anything different compared to the pages that worked: other than non-code text and filenames, everything was the same.
• Changed the publish date of the new post to match the dates of previous posts that are working correctly (in case there was a 2016-related bug): no change.
• Moved the post to an earlier position/order: no change.
• Duplicated an old page that correctly appears in the image/text list: the duplicated page did not show up in the list/images.
• Removed a few pages to see if we had hit some sort of thumbnail limit: the old, previously working pages were removed, but the new pages were not included.

Any other suggestions? Thanks!!

https://wordpress.org/plugins/autonav/