The other AdMech transport got released without any big book alongside it as well.
It was, but I got the sense that both it and the Astartes' Executioner were bumped up from their slots as part of support waves in 2020 so that GW could pretend they actually had some tie-in products for the Apocalypse release. The Executioner was really a square peg among this year's Vanguard releases and the Skorpius could very well have been planned for release alongside the Archaeopter and the Hephaestons, plus whatever else.
Edited by Chaplain Dosjetka, 03 December 2019 - 12:49 PM.
Edited title and tags.