I did a little digging. It maybe related to mixed content.
https://www.reddit.com/r/firefox/comments/awjvyd Related documentation:
When a user visits a page served over HTTPS, their connection with the web server is encrypted with TLS and is therefore safeguarded from most sniffers and man-in-the-middle attacks. An HTTPS page that includes content fetched using cleartext HTTP is called a mixed content page. Pages like this...
Could this be fixed?