@simon I have resolved this issue.
In order to solve another issue Unable to generate preview for URLs - #4 by seeminglee — i have enabled HEAD requests on the site, and now all of the discussions showed up, and in turn, threads get automatically generated for my blog posts.
This is amazing — I can’t believe that I’ve gone down the rabbit hole of trying to determine if it’s a CORS-related issue when it’s related to HEAD requests. Perhaps this needs to be specified somewhere in the docs.
Please consider this issue closed.