If you played a rogue in Legion, you'd know that SI6 was infiltrated by a Dreadlord who fed misleading "intelligence" to Genn and Anduin. And of course we all know Sylvanas was up to something in Stormheim that was probably best interrupted anyway, so it may have worked out for the best. Regardless of that, I suspect we'll find a 3rd party behind it all yet again.