Stuck on Postgame Quests

[Liir]

Spoiler

I'm currently stuck after getting

 

Spoiler

the BAD END screen in Distorted Space after catching Giratina. The controls don't seem to respond and even soft resetting sends me back to the same screen (forcing me to reload a save file), except I get a dialogue box from Anna telling me to 'find the Gold and Ivory Keys and try again'.

 

All other active quests are also stuck, namely the one in Aegir Cave where I need a Rayquaza, the one in Rhodochrine Jungle where I need a 100% Zygarde (I have 50% Zygarde and 64 cells) and the one in the desert factory, also related to Zygarde.

 

Here are the things that I've already tried:

 

(1) Talked to every NPC in the Nightclub;

 

(2) Talked to every NPC involved in the above mentioned quests;

 

(3) Tried fainting the Giratina instead of catching it (this immediately restarts the fight);

 

(4) Tried changing the inverse field during the Giratina fight (sort of like you have to set it up during the first Malamar fight in Distorted Space);

 

(5) Tried to find a way back into Subseven Sanctum since the Gold and Ivory Keys are mentioned in the books found in there, but it's inaccessible since it was burned down by Luna and Taka;

 

(6) Went back to the Deoxys meteor to see if Zina would show up again, since she sent me to Byxbysion in the first place, but she's not there anymore;

 

(7) Looked at the crosses in the Elite 4 building. There's 3 of each colour: Amethyst, Emerald, Ruby, Sapphire, but also Gold and Ivory, but if there is some kind of pattern to be deduced here, I can't see it...

 

I don't know what else to do. Is my save impossible to complete? If so, how far back would I have to reload to get myself out of this situation?

 

Btw, this is on a save that was complete as of E18, not sure if that matters.

 

[Glynda]

Spoiler

For the Giratina quest: That's bad ending screen is a bait and switch. What i did was just keep resetting the game and eventually Anna dropped it and allowed me to continue. I saved between each iteration so i don't know if that has any influence at all, but keep a backup just in case.

As for the Zygard and Groudon/Kyogre questlines: Those are actually supposed to be holdovers until you can get the necessary legendaries to continue. Rayquaza is a Tier 7 legendary so just do the other quests until you unlock it, and the Zygarde questline can be completed as soon as you see Marcello jumping again in his spot. He'll tell you to go back to the desert factory, and you'll be able to complete the quest there.