Stellaris - Pre-war sides do not match actual war sides. Cepheus 3.4.5 (a361)

[Mallow95]

Description
Pre-war sides do not match actual war sides. Cepheus 3.4.5 (a361)

Game Version
Cepheus 3.4.5

What version do you use?
Steam

What expansions do you have installed?
Synthetic Dawn, Utopia, Leviathans Story Pack, Apocalypse, Megacorp, Distant Stars, Ancient Relics, Lithoids, Federations, Nemesis, Aquatics

Do you have mods enabled?
No

Please explain your issue is in as much detail as possible.
Single player, ironman

Playing as: Lavis Confederation. President of Hegemony Federation named Galactic Root

Declared war on Till'Lynesi Directors (Awakened Empire)

The war proposal screen showed that my Federation would join the war on my side. A majority of my Federation voted to declare war. Once war begins, my entire federation is immediately on the side of the Till'Lynesi Directors, against me. We are still united in a federation and I still have control over the federation fleet.

Of note, the Democratic Thembolon Sovereignty is a Scion of the Till'Lynesi Directors and also a part of my federation.

I have tried to reflect all of this in the screenshots but I have included my save file as well.

Steps to reproduce the issue.
1) Be in federation with a scion empire.
2) Declare war against the scion's overlord.

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