Presumably the content which was to be Rumoured was to be part of the DLC which, you'll remember, was originally supposed to arrive at the same time as 3.3.
Well, that didn't happen. We won't be seeing that content till late 2020 (if all goes well). Are Frontier in the meantime going to divert resources from the development of the new DLC to provide us with content that can be the subject of Rumours before then? Who knows? But my guess is that Frontier want the new DLC, when it finally arrives, to make as big a bang as possible: they're not going to reduce the impact of any of its features by running minimum-effort - and it would be minimum-effort - precursors beforehand.