Even if it is retained as canon, it could be treated as an operation that was cancelled.
It actually works well with the canon for that time. Era Report: 3052 makes it clear that the Great Houses were putting their most brilliant minds in rooms and devising plan after plan. A lot of them designed to slow down the Clans, and a lot of them failed, and sent everyone back to the drawing board to devise yet more plans. That also probably means a lot of operations were stood up but cancelled during this chaotic period.
This could be taken as one of those plans, that was formulated, brought to the Coordinator, nearly put into action but then was cancelled, for a dozen different reasons. Or delayed, but delayed long enough that the victory at Luthien happened, then caused the plan to be reconsidered.
Whatever way it panned out, I can't find any references to it besides what you all are telling us the novel says. It does make sense to me that the Coordinator and the DCMS would have some kind of plan for some attempt at an offensive action. After all these are the same brains who executed the DCMS counterattack during the War of '39. It sounds very akin to that.