Auto Weapon Set Swap Bug on Casting Spells [/w potential "fix"]

Background: Witch character, Act 1, at the Manor.

Items/Gems: A bit unconventional, but works: using sceptor for the skeleton warriors in right hand, and focus twit on right hand. Dmg is from Essence Drain so it's NOT weapon set dependent.

Issue: For some reason, whenever I cast Essence Drain, the game auto-swap my weapon set to Set 2. This appeared for no apparent reason and I cannot undo it. Note that I've never even use my set 2, it's mainly for looks (emergency, for mana drain whenever I run into mobs with mana drain aura), but in most cases I can chuck enough mana portion to never use set 2. Note that until this point, I've been playing with this setup for many maps... and never had a problem. Cast Essence Drain and it'd always stay on Set 1. But somehow, maybe since I started learning how to use the Weapon Set Passive Allocation, it started getting bugged?

Attempted fixes: I tried to unequip all my items and cast bare hand... it still swap to Set 2 despite Essence Drain is NOT bound to any weapon, it's a skill slotted.
Tried to clear all the hotkeys mapped, then remap to different locations/keys, such as mapping Essence Drain to Q. Nothing.
I even unequipped my gems, make sure I have nothing, then reequip them in different order/slots, the bug still persist.
In fact, to make it more annoying, I tried to put the sceptor into weapon set 2 then cast Essence Drain... and the game swaps my set into Set 1!
On a related note, the game does this not just for Essence Drain, but also just Punch.

TL;DR: Whenever I Punch or cast a specific slotted skill, the game auto-swap my current weapon set to the one that I"M NOT USING. It doesn't matter which button I map the skill to, it'll always auto swap. It happens to that skill (Essence Drain) only, but not any other skill, so far.


This is super annoying and basically breaks my current build. I'm forced to play with a different build. that doesn't use Essence Drain + Contagion... which I had to go respec for no reason. I have no idea how this happens. Maybe the assumption is we'd be using one of the weapon skills, except I think they are meh so I don't use them.

-----

EDIT:
"Fix": To make sure I'm not going crazy, I did several things and it worked:
1. I respec'd away the different weapon set passive, so basically, I only have one passive tree, not two.
2. I unequipped all weapons and unslotted the Essence Drain gem before teleporting to town.
3. Travel back to the map, then first I equipped the gem, then I equipped the weapon. And no more swapping.

I suspect the two weapon set passive might be a contributing factor, but honestly anything could trigger the bug.

Happened to me too. I think the unequipping in town and reequipping in zone worked, i didnt respec any points in the tree.

I'm not sure if I faced a similar problem, but still. I also play the Witcher class and when I equip a scepter in slot II, but switch to slot I, I can still summon skeletons from the scepter even though the scepter is not currently the active set.
The same happens with weapon passives: sometimes the Hero stats show that they apply even though if you set the different active set.
However, sometimes these skills become inactive: skeletons disappear and passive don't work more.

I don't have any idea how this is expected to work. My previous experience in games gives me idea that only active set should apply active and passive skills. Thus, this makes me feel that this is a bug.

same bug

same bug, ranger; happened after equipping conductivity in an empty skill slot; tried some stuff, apparently it got fixed after i equipped a shield in my off hand (was empty before), bot sure though