It would seem that any page that uses the frontpage view picks up the wrong canonical URL.
In views.php, the URL being passed in for such pages has the option but no more information. It is then routed to the appropriate menu item. In my case, that's the one with the alias of "entry." Whether I pick default or a specific menu ID, it always picks up SOME menu item.
But since this is the home page of the site, the canonical URL should not have a path. It should be the root url.
Here is some debug output I made in views.php:
Pre URL: index.php?option=com_easyblog
Post URL: https://www.retrograde.today/entry
As you can see, the URL in is the component only, as it is coming from my home page which is of type Easyblog/frontpage.
The canonical URL being set should be simply https:/http://www.retrograde.today
The IDEAL solution would be an option on the menu item to OVERRIDE the canonical URL for that menu item. I'd then set it to the URL for the site and be done.
Either way, the canonical URL as set now is wrong.