AE Mechanics for forced vassalizations seem a bit wonky

[Dnote]

I just vassalized a OPM in a random nations game within the British Isles who I had a claim on, every other nation on the isles immediately gained +40 AE and formed a coalition. War broke out shortly afterwards.

Never experienced AE like this before for taking a vassal, rather annoying.

 

[Dnote]

Just vassalized a second nation, two provinces, another +40 AE, coalition against me now contains every nation that would be modern day France, Belgium and Netherlands.

AE is messed up.

 

[Dnote]

The amount of AE given seems a little high to me, but I don't usually pay too close an attention to the numbers, what surprising me more is that +40 = instant coalition with all my neighbors, then a further +40 added a dozen more countries from across the sea.

I don't coalitions forming that quickly outside of the HRE.

 

[Dnote]

I've noticed similar issues, I think it might be a function of the new "AE drop off is centered on vassal capital" that was introduced in 1.10 not working correctly. AE gained from forced vassals seems to splash across entire regions in ways that AE gained from taking provinces does not.

This does seem to be true and I find it a little strange for that to be the case. Forcing a vassal shouldn't have as much AE as straight out annexing.

Anyone know the numerical value of AE to make the AI join a coalition? 40 seems a little low to me given how much war is a part of the game.