@ytrewq This is an Update: Uninstalling and then reinstalling Opera removed the problem pinned-link.
Prior to uninstalling, I copied several key files from the opera installation (e.g. bookmarks, setting, extensions, etc) to another folder, then did a copy-replace of the same files in the new Opera installation to recover all setting, extensions and bookmarks. The operation was successful.
I have noticed that with the current version of Opera I can no longer drag-n-drop links to pin them to the pinned-Opera Icon in the Taskbar.