@leocg I'm getting a similar issue, and it appears to stop Facebook from completely loading. In your newsfeed, you get 2 articles and a "more stories" placeholder at the bottom of the page. When you scroll down, you should see more articles loading (i.e. infinite scroll). On other browsers like Chrome, this works but it has stopped working in Opera about a week or so ago.
Looking in the console, I see a lot of messages saying "Opera has modified script or content on www.facebook.com (PATCH-1195, Facebook - block first character in the comment field from triggering a single key keyboard shortcut). See browser.js for details"
In addition I also see an error thrown: "P31kdubUtWR.js:57 ErrorUtils caught an error: "Missing dependencies: JS::call("TrendingHovercardLogger", "registerHovercardF...". Subsequent errors won't be logged; see https://fburl.com/debugjs."