Can't find an answer anywhere, but I'm having a problem supporting a vassal

[JumpingHornet]

Basically, playing a custom norse ruler of mallorca in 867. Declared independence from my duke liege, and defeated him, created the duchy of Sardinia after a few invasions, then got the kingdom itself. My liege is the emperor of the Carolingian Empire.

Few years later and his rival, another Karling, and my friend, creates a faction to make himself emperor. I join, and he eventually asks for my support. However, I can't find where to actually support him... It said to do it manually, or lose prestige, but I don't see a decision to do this. Joining his faction didn't do anything, and I don't know what to do. I want this new guy to be the liege so I can buy a favor from him, but I can't give him support even after joining the faction.

Does anyone know how to get this to work, or am I just bugged out? I tried reloading my save, but it didn't do anything, once he eventually asked again.

 

[Deltasquid]

You're supposed to join his faction. I'm not sure what you meant with "didn't do anything", as your strength should be added to the faction. If you promise him to support him and don't join the faction, you get an event 2 months later from him where he insults you for breaking your word. Did that happen when you joined?

 

[JumpingHornet]

I joined the faction, got the warning that if I didn't join the event would happen (this happened after I was willfully forced into after accepting when he asked me to join) and then 2 months later he sent me the insult, and the war broke out with me as his enemy, and I was still under my original top liege.

I was a part of the faction, but the game made it seemed like I never was. I reloaded my save (that I no longer have sadly) a few times to double check, and I didn't forget anything. It just didn't register.

Odd, but it honestly wasn't a huge deal at that point as I declared independence right after the war broke out and easily won. I assume it'd be a tougher situation if I wasn't a king, but instead a count or duke trying to gain independence.