[curt.clifton]

It's probably not considered a bug. OF doesn't let you add actions in context mode under the assumption that you can't see to what project you're adding the action. Since Duplicate adds an action, it is probably being disabled.

It seems reasonable to put the duplicate in the same project as the action being duplicated, but then there's another confusion. What if the project is sequential? The duplicate won't appear because the original is blocking it.