The World of Catara

I Didn’t Roll Good Enough Bug:
There is a variable called X2_L_BEH_COMPASSION. It’s a nice variable, that makes an NPC heal other NPCs. It even works on Rogues who have Healing scrolls handy. However, this variable has a really weird side effect. It will make an NPC cast the same buff on itself over and over and over and over if it has multiple castings of it.
I haven’t found a way around this except to simply not give any NPCs I want to heal others more than one casting of the same buff, however.
Healing, Yum! Bug:
Again, not quite a bug so much as quirky behavior. NPCs will normally heal themselves when they fall to ‘badly injured’. If they are hidden by invisibility however, they will heal themselves if they have taken any damage AT ALL. NPCs will plow through their heal potions in no time if something happens to be hitting them while they’re invis.
Papercut? Heal Potion. Grass stain? Heal Potion. PC called you a nasty name? Heal Potion.
Unfortunately, I don’t know a solution for this except to have a custom AI that runs 100% of the time on the NPC in question. Since this causes lag, it’s not a viable solution for most spawns. Sorry folks, no way around this one, just have to accept it.
Archers Hate Magic Bug:
There are four default AI sets included with NWN, which you can call for NPCs to alter their behavior. One such AI is a handy one which makes the NPC use rapid shot, occasionally run from people trying to melee it, and switch back to it’s bow often so if a PC gets close and then runs away again, the NPC archer won’t chase after them waving a dagger around yelling ‘Get off my lawn!’ or whatever grumpy old archers yell.
Sadly, Ranged AI (as I call it) has a downside. It won’t use magic. No spells, no potions. Custom AI scripts can fix this, but unless that AI is constantly running and tells the NPC to renew it’s buffs all the time, an NPC with Ranged AI will never cast spells again.
No solution for this. Just keep it in mind when making archer NPCs if you intend to have them use Ranged AI.
That’s Not My Spell List Bug:
NPC spell lists are fickle things. They breakdown and stop working if you look at them the wrong way. Here are a few of the things that will cause your NPCs spell list to become completely fubar, often stripping them of half or more of their spells.
Build Module. Yes, if you actually let the “Build Module” command run all the way through, it will randomly mess up some NPCs spell lists. Haven’t quite figured out what causes an NPC to be affected or not, but it definitely seems if an NPC uses metamagic, they’re more likely to get hit by it.
Placing A Metamagic Using NPC Directly: If you have a metamagic using NPC, and you place him in an area via the toolset instead of having him spawn from an encounter or a script, his spell list WILL be messed up. At least for me this would happen 100% of the time. Not a really huge issue though since placed NPCs are usually just for socializing.
Reset To Parent Faction: Every time you export something, the toolset asks you if you want to ‘reset to parent faction’. This sets the NPC to one of the original four factions (Defender, Commoner, Merchant, Hostile), the result of which depends on what the creator of a custom faction choose as the ‘parent faction’. If you select this option, it will mess up your NPCs spell list. I just learned this one today, finally ending my question of why several of my NPCs had bizarrely messed up spell lists outside of the Wilderness server.
Tensers and Shapeshifting Is Against My Religion Bug:
If cast by the default AI, the spell Tenser’s Transformation and the various polymorphs will not work. At all. They don’t actually do anything. These spells may work if called by an AI, but I’m not certain as I haven’t experimented with it
I Hate Casters Bug:
Occasionally, an NPC will turn on an NPC caster ally and start attacking them. You'll notice they do this when hit by an AoE, so you THINK you know the cause for it. It's the AoE, right? Well, you're only half right. Turns out, most NPCs have the common sense not to kill themselves by beating their Acid Sheathed caster buddies in a sudden display of Mage Hate. What makes an NPC turn on their allies is actually the Sneak Attack ability.
I guess Rogues are just less inclined to take crap from mages, but only NPCs with Sneak Attack will actually ATTACK allied casters who hit them with spells. And only spells with long lasting effects cause them to really do this. Negative Energy Burst, Darkness, or other AoE's with long durations cause the rogues to attack the casters, sometimes even after the battle.
There's a quasi solution to this. If you give the NPC Sneak Attack, Blackguard instead of normal Sneak Attack, they seem less inclined to spontaneously develop a hatred for everyone who likes wearing bathrobes. So give NPCs blackguard sneak attack instead of normal sneak attack whenever you can. But be careful, Blackguard Sneak Attack (4d6) doesn't work at all.
Darkness seems to have the highest chance of causing this friendly fire. I guess rogue NPCs find it really insulting when they get free sneak attacks on PCs.
Clouds, clouds, clouds, Bug:
Not a bug, but an AI quirk. If an NPC is capable of casting tons of cloud spells, such as stinking cloud, Evards, Cloud of Bewilderment, or any other lingering AoE...he will. He'll cast tons of them, paying no heed to whether he's standing in them or if all his enemies are crashing from having 42 Clouds of Bewilderment running at the same time.
To put it mildly, if you're going to make a Sorcerer NPC, or a Wizard with a lot of Clouds, please make sure they don't destroy the internet every time they see an enemy. Make sure to use X2_SPELL_RANDOM if you must give them that many clouds, but if you can avoid it, simply limit the amount of clouds they'll cast
But That's Not A Person Bug:
The spell Hold Person has a number of problems with it in regards to the AI. You will, however, rarely see these problems, because all of the standard races don't incur them. If, however, the NPC is faced off against an opponent who is NOT one of the standard seven races, the AI will suddenly go "I'm not casting that spell, it won't work." So far, so good, except the AI's next move is always charging the person and hitting them with a stick. I don't know why, exactly, but something about wanting to cast Hold Person and the opponent not being counted as a "Person" just offends the AI's senses so much it spontaneously explodes and resorts to randomly punching the nearest object. Or sometimes it just stands there pondering the meaning of life until somebody slaps him.
Even the almighty X2_SPELL_RANDOM won't stop this bug, though it does make it only last for one round. Namely, each round the NPC WOULD have cast Hold Person on the non-person, they will instead charge or stand around doing nothing, then next round they'll pick another spell from their roulette wheel of happy funtime spells and continue as normal.
Luckily, the solution is pretty obvious: Don't give NPCs Hold Person. Or, if you do, make sure you're okay with them pretending to go AFK randomly.
Note: Hold Person DOES work on creatures besides the standard seven races on Avlis. The AI, however, is unaware of this fact.