Hi CA staff,
I was playing as Heralds of Ariel and confederated Wargrove of Woe. The UI for recruiting regular Ancient Treeman Lords was replaced by that for Malevolent Ancient Treeman Lords which are exclusive to Wargrove of Woe. Hence I was unable to recruit both old and new regular Ancient Treeman Lords from the moment I made the confederation and onwards.
Confederating Wargrove of Woe playing as Heralds of Ariel (or the remaining two Wood Elves factions presumably), and then accessing the UI for recruiting Ancient Treeman Lords.
The concerned save is attached.