[2.6.2] I get alliance-breaker when joining war of my ally

[Timmay_H]

NOTE: I accidentily made a mistake with the game version as I am currently playing version 2.6.1.1. I don't know how to change the title.

Active DLC: Conclave, Legacy of Rome, Sons of Abraham, Old Gods, Sword of Islam, Way of Life
Mods: None

So the following happened to me twice this game. As duke of Normandy I successfully helped my brother (or nephew, I'm not sure) with his claim on the duchy of Mercia. Immediately after that I formed an alliance with him. After a few years my brother had to fight off a revolt. I offered to assist in his war and at the same time I received a request from him to join his war, so these actions happened simultaneously. As you can see in the screenshot I did join the war and we stayed allies, but I also got the message that I broke the alliance with my brother resulting in a severe penalty in general opinion. As this is the second time this happened to me I strongly think this is a bug.

 

[Red Earth]

This happens with other things too. If you try to go forward with a marriage after a betrothal you often get a message asking for the promised marriage. If you accept then you'll get a message in a few days refusing the marriage, although the marriage has already taken place, because it's no longer a valid action for married characters to marry again so it defaults to refusal.
Also happens with end plot. If you get the plot leader to end a plot while still waiting for a response from plot supporters, then the supporters will all refuse because leaving a plot that doesn't exist is an invalid action so it defaults to refusal. This is an exploit because refusing to end support for a plot is grounds for arrest, giving you tyranny free imprisonment on characters who may have never dared refuse your request.

I never bothered to report these because they didn't do any harm and they happen so often that they must already be known, but alliance breaker penalties are severe and could screw up your plans so now it needs to be addressed.

Perhaps the game should have awareness of what request actions are executable both ways and cancel the ability to send such a request once the other side has already sent theirs.
Have the first raven eat the second to avoid confusion.