View Single Post
Take the one you want to keep and rename it to Miscellaneous.keep. Delete the other one. Check your OmniFocus preferences and make sure that it has Miscellaneous.keep as the default single action list. Now sync your Mac on which you did all this, followed by your other devices. Go back and rename Miscellaneous.keep to Miscellaneous, sync the Mac, sync the other devices. In my experience, that should do the trick.