The Saving Throw at the end of every turn is also how Crown of Madness and Hold Person work in BG3.  While fixing this, we also gave the spell its tabletop duration of potentially 10 turns (instead of 3), though in practice most creatures will succeed a Saving Throw within the first 3 turns anyhow (read: probability).  The mod does not otherwise alter Confusion nor its effects/status (which we detail below).

Useful tactical info for fun / How Confusion works in BG3 :
This is how Confusion works, by default in BG3, even without the mod.

• First, it has no effect on allies, which is nice.  If unfriendly targets (red or yellow) are not in combat, the Confusion status will not make them attack anything yet and they might even start making Saving Throws every 6 seconds. You will need to trigger combat (sometimes just getting closer might do it) for Confusion to work normally. 
• There is 50% chance a Confused target will do nothing (Stupor) and 50% chance they will randomly attack creatures within their range (In the game files, Stupor is called "Confusion_Skip", while the hostility [attacking anyone] is called "Madness"). 
• Confused targets, when hostile, will not necessarily attack the closest creature, but instead the AI will consider everyone an enemy and will use its own combat scheme. In short, if there is no one else in combat, there is 50% chance it will fight pretty much normally. 
• This mod does not alter any of the above. 
  

Does it affect other cases of Confusion and does it affect the player characters ?

Yes, your characters follow the same normal rules against Confusion effects : you get a Saving Throw when you are hit by a Confusion effect; if you fail, you are affected on your turn as you should be; and you get another Saving Throw at the end of that turn. Fair.

The Confusion status or effect is used by a few NPC attacks, such as Mindscreech from "Nurses", Rolan's Colorspray, and a Spectator Ray.  They use the same Confusion code and it works the same way.  So both your party and enemies follow the same rules as written. 


Is it safe to remove or replace this mod ? 
Since this mod only tweaks two "stats" files, without altering any icons, items, etc., my understanding is that it does not affect your save files in any way.  Removing this mod or replacing it with another Confusion mod should not affect your saved games. 

Installation 
This mod was made for Patch 7 (with the Toolkit) and will not work with Patch 6.
( but I added an optional version that might work for Patch 6 ) 

You can ...
a) use Vortex (should work: report any issues as I have not used it for BG3) 
b) use BG3MM [link: GitHub, latest release] (tested on my side as working great) 
HOW:

• click File > Import Mod : find the file ConfusionSavingThrowFix[...].zip (or .pak) 
• move the mod from Inactive Mods to Active Mods.
• IMPORTANT: once you like your load order, make sure to click Export Order To Game. 
  

c) or use BG3's internal mod system.  

Important : if you install an official mod, while you also have third-party mods, remember that you MUST exit the game and reassert the new load order (modsettings.lsx) with a mod manager like BG3MM (I presume Vortex does it also) ; otherwise your save will not load (it will hang, because the "story" will not load). 
    If you install a third-party mod, while you also have official mods, the process is simpler but it still boils down to making sure the file modsettings.lsx is updated.  

Analysis - Nerd section or design thoughts : 
By the way, don't hesitate to disagree or make suggestions ...

- Crown of Madness and Hold Person (both level 2) place the Saving Throw at the end of the turn, as it should be.  I presume the designer wanted the random Confusion effect to trigger on the start of the turn, but saving twice in a row before ever being affected is of course not right; especially for a spell where there is about 50% chance the enemy will still attack you even if they failed both saves...  Confusion is powerful in any case when used on numerous targets, but I found this issue or bug discouraging and had simply unprepared it.  

- The fix applied with this mod does procure another advantage in practice: you can see that the affected target will either be hostile or be in stupor on their next turn.  While this is more predictable then being rolled at the start of their turn, it is similar to what many other spells do, like knowing the target will be affected by "Madness" (Crown of Madness) or be paralzed (Hold Person), etc.  I feel this difference is minor or superficial in comparison to the issue of the initial double saves. 

- Duration : the tabletop *potential* 10 rounds is very improbable and I estimate that in most cases Confusion will last 2 or 3 turns.  Still, I estimate that most people who want this mod might prefer something closer to the tabletop rules.  Tell me if you feel we should limit it back to 3 turns maximum. 


- Speaking of the tabletop Confusion spell (both 2014 & 2024), it actually has 4 different effects (10% random move; 50% stupor; 20% randomly make one single melee attack; 20% act as normal).  Implementing them would be much more complex!  The current version of Confusion is fine in my opinion and this mod is a simple quick fix, but popular demand could spark me or other modders to make a 100% tabletop version of Confusion. That said, note that modifying the "Madness" status can cause bugs and crashes as it is used by some special enemies in the game against the player (this was discovered from another mod). Mind you, a tabletop adaptation could simply give 20% chance of having the Madness effect.  I would argue that the BG3 implementation (50% chance of Madness) amounts to about the same thing, albeit much more dangerous than a single melee attack, but on the other hand the tabletop version has 20% chance that the enemy will act as they wish. 
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Nb: this mod is also available in BG3 own mod system.