I'm sorry, but I can't believe that this can't be reproduced. Everybody having this issue, the mods or no mods, even the ones who plays on consoles, where you can't use the mod. So my only guess is that your test team uses different build of the game with different files, that the actual players use. Again it's only my guess, based upon my little research.
So I used the console with this commands: "Ciri" - to change the appearance to Ciri as playable character and the "spawn('cirilla')" to spawn NPC Ciri near me. This is the result:
Then I go to the content\gameplay\items\def_item_weapons_secondary.xml and find there this line:
This line is under the Ciri swords description and the scabbard is bound to her sword. And then I thought "What is "player_override"? What this line do? Could it be mean that the attribute "bound_item" will only work if this character is a player? Lets find out!"
So I changed this line to look like that:
And the result was this:
I don't wanna teach nobody to do there jobs and I don't wanna offend anybody. I think that CDPR did a great job and made the best game ever. For me Witcher 3 in all games is like Empire Strikes Back in all movies.
But since patch one the debugging of the game was a mess. And again everybody in the Witcher team are great, you added so much to the game since it's release, and fixed so much, thank you for that, I understand that this no easy. But you also added many new bugs.
As a fan, and the one who think that this is the best game ever, I want it to be bug free. And I many times used your contact form to report bugs, to achieve that, but I won't use it again. Because it's really frustrating for me, I have to PROVE that the bug exists, like really prove that, instead of just telling that it there. And after I take screenshots, make a video, and send a save files, after spending halve a day catching the bug and presenting my case, the support still will say that I'm using the mods or that I should try to verify game files and that they can't help me, even thought that it's you who need help and I trying to help YOU. I'm not a noob, I can understand whether is not the bug caused by the mods I using or by the file corruption. Long story short, I think that you need a better contact form.
As for this bug, I don't know whether or not removing this line from .xml file is right thing to do or there more to it. But this fixes the issue.
Sorry for any mistakes, English is not my native language.