Is it possible to fix this major issue?
Auramagma pointed out what I'm going to say in less words... Is this something you've experienced in-game? Because while Brad mentions it, he also says they did a lot of coding to get around it, without knowing what was the issue to start w/. In other words, it's quite possible we aren't really experiencing this despite the bug (Sorcerer King is a different case because of Minor Factions AI).
I guess what I'm saying is I'm not sure this cripples the Faction AI in LH at all. Other than that, Brad doesn't really say if Wild AI is affected by this, but generally Wild Creatures don't go beyond a certain number of tiles from their lair, so that sounds more or less irrelevant where Wild Creatures are concerned, unless this solves the issue of Wild Creatures rarely attacking Faction AI Cities. The one AI I could see being affected by this is Wildland AI. Wildland Creatures are generally rather uninterested in players until player units step inside the Wildland Stamp. Considering Wildland Stamps have a specific Continent ID (like most Stamps anyway), it's possible there is something at work here. In summary:
Faction AI, not seeing the issue;
Wild AI, not seeing the issue (unless...);
Wildland AI, might be seeing the "issue".
Assuming what I just pointed out about Wildland AI is true, I will say I'm perfectly fine w/ Wildland AI being somewhat uninterested in players until player units step inside the Wildland. Makes sense to me considering Wildland Creatures are there to defend the Wildland before anything else. At the same time, this likely lowers the incidence of Wild Creatures vs Wildland Creatures battles. Otherwise, Wild/Wildland will self-clear.
All that being said, I've checked the Vanilla Stamps and assuming (again) that the problematic tag is ContinentID ###, then I don't really see a problem switching them to ContinentID=-1(other than the fact there is close to 100 000 such tags), but that won't be added to XtraDeconstruct (for now anyway), until I can figure what the issue really is and how it affects players. You can try it if you want:
Version A [Dropbox]
All Vanilla Stamps (133 Stamps) now using ContinentID=-1.
Version B [Dropbox]
Same as above, minus the Wildland Stamps (110 Stamps).
1. Make a backup, somewhere on your hard drive (NOT in the LH folder, obviously) of your Core Stamps folder.
C:\Program Files (x86)\Steam\steamapps\common\FE Legendary Heroes\data\English\Core Stamps\
2. Extract zip file in said Core Stamps folder (Use "Extract Here", do not create a new folder as you must overwrite old Vanilla Files)
Let me know (preferably in details) if you notice differences.