CK II - I can give my kids their siblings as concubines/consorts

[Zoomun]

One line summary of your issue
I can give my kids their siblings as concubines/consorts

Game Version
3.0.1

What expansions do you have installed?
All of the above

Do you have mods enabled?
No

Please explain your issue is in as much detail as possible.
Without picking divine marriage I'm getting the option to give my sons their sisters as concubines and give my daughters their brothers as consorts. I'm playing reformed Slavic with Equality/Meritocracy. I know this is CK2 and incest is everything but I don't think this is intended.

EDIT: Just found out I can give them their parents too
Steps to reproduce the issue.
Reform a pagan religion with Equality
Offer a concubine to your kid

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[Arrnea]

I've seen this happen too, as reformed Tengri.

 

[Kregritt]

Heh, I just assumed that it was a problem with one of my mods, but it seems that it's a vanilla thing lol