It looks like that’s a custom action defined in the Shortcuts app, not part of OmniFocus itself. So I’m not sure what it’s expected to do!
What I usually do to share a webpage with OmniFocus is use the Share button, then choose the OmniFocus app.
This brings up a Quick Entry window with the title of the web page and its URL already copied in. For example, if I do that on this web page I get a Quick Entry window that looks like this:
Another built-in option is use the built-in Clippings service. Select some text, then send it to OmniFocus by choosing OmniFocus 4: Send to Inbox from the Services submenu in the app menu. This can be assigned a system-wide keyboard shortcut in the System Settings app (under Keyboard > Keyboard Shortcuts > Services > Text).
If I select the first sentence on this page and use the Clippings service, I’ll get a Quick Entry window that has that text along with a link to the page, like so:
Returning to the question of the mysterious “Share Article to OmniFocus” action, you can look for that in the Shortcuts app to see what it is. Maybe it was defined for a different platform, but synced everywhere and that’s why it doesn’t work? Or maybe it tries to use actions from an app that’s not installed? Maybe it’s no longer needed, and you can simply delete it.