It could be that the functionality of the extension/program was damaged due to an unsuccessful update.
We recommend that you remove and reinstall the extension, and if the issue still persists, uninstall and reinstall the program.
On a Macbook pro, Monterey 12.1, F-Secure 18.0: With Safari 15.2 extension turned on F-Secure stops web pages from finishing loading. Reloading fixes most occurrences but not all by any means. So I run with extensions OFF for now. Any cure for this or upcoming fix?