Updated after more testing as Shadow Legion (making sure corruption not affected by shared provinces)


Overall, many of those Tech bugs  seem related to load game not correctly recognizing what gifts are active at the state when a save game was made.


Undivided Gifts : 

Dark Diplomacy: gives +45 diplomacy with Norsca / Skaven / Beastmen (shows as Technology) with 3 gifts after changing an undivided gift, does not show after Load Game, but comes back after changing undivided Gift or End Turn.


Mono Gifts : 


+1 Slaanesh / Khorne / Tzeentch / Nurgle Authority from active gifts , does not properly show every time at Load Game , sometimes need 2 changes to gifts (2 turns), and End Turns to fully fix itself.



Corruption / Altar Techs :


Bloodied Blade 

+2 Khorne Corruption from Chaos Altars , added to Ritual Hut instead of Chaos Altar (and Barricaded Chaos Altar) so cannot be built in Ports or Forts. (Tech Also applies to the Sorcery building chain, but tech does not specify that)


+2 Khorne Corruption per active Gift of Khorne, only gives +1 Khorne corruption instead of +2 per gift (for both undivided and Valkia factions,  but goes away after Load game. (need to change gift to re-activate) and then end-turn, (some situations seem to need you to change more then 1 gift to get the full bonus back)


Enchanted Idols 

+2 Tzeentch Corruption from Chaos Altars , added to Ritual Hut building instead of Chaos Altar so cannot be built in Port. (Tech also applies to the Sorcery building chain, but tech does not specify that)


+1 Tzeentch Corruption per active Gift of Tzeentch, gives 1 corruption per gift , but goes away after Load game. (need to change gift to re-activate) , and then end-turn  (some situations seem to need you to change more then 1 gift to get the full bonus again)


Swamp of Souls 

+2 Nurgle Corruption from Chaos Altars , added to Ritual Hut building instead of Chaos Altar so cannot be built in Port.

(Tech also applies to the Sorcery building chain, but tech does not specify that)


+1 Nurgle Corruption per active Gift of Nurgle, 1 corruption per gift,  but completely goes away after Load Game. (need to change  gift to re-activate) ,  and then end-turn , (some situations seem to need you to change more then 1 gift to get the full bonus again)


Corrupted Offerings 

+2 Slaanesh Corruption from Chaos Altars , added to Ritual Hut building instead of the Chaos Altar so cannot be built in Port. (Tech also applies to the Sorcery building chain, but tech does not specify that)


+2 Slaanesh Corruption per active Gift of Slaanesh, only gives 1 corruption instead of 2,  but completely goes away after Load Game. (need to change  gift to re-activate) , and then end-turn, (some situations seem to need you to change more then 1 gift to get the full bonus again)


Altar Techs not applying to Chaos Altar as the tech seems to suggest but the sub-building from altar : Ritual Hut , which means it cannot be built in Port cities or Forts , and shares a lot with Defense / Loot / Resource buildings . (if intended, the Tech text should be changed to Ritual Hut.


Also , the tooltip on Ritual hut is in the wrong order, as Nurgle and Slaanesh corruption are below the text  of "when Technology researched"