Started my own Kingdom (without doing quest) - Can't change background color and my newly recruited lords retained previous faction colors

[Midnitewolf]

Trying to figure out how to fix this.

I knew I was going to be a Vassal to Vlandia so I created my original flag with red background and yellow symbol. Decided to do my own Kingdom by leaving and keeping my fiefs but when I went to change my banner, all I could change is the symbol color. That wouldn't be an issue but my newly recruited vassals seem to have all taken over the original Red and Yellow of my original banner and once I gave them a fief, their symbols and banners all stayed Red and Yellow which look exactly like Vlandia's colors so I can't tell my Kindoms fiefs from Vlandia's fiefs.

How do I fix this?

 

[Stromming]

Did you reload your game?
I had the issue that some clans kept their colours too, but then i just saved and reloaded and it was fixed.

 

[Yertyl]

Trying to figure out how to fix this.

I knew I was going to be a Vassal to Vlandia so I created my original flag with red background and yellow symbol. Decided to do my own Kingdom by leaving and keeping my fiefs but when I went to change my banner, all I could change is the symbol color. That wouldn't be an issue but my newly recruited vassals seem to have all taken over the original Red and Yellow of my original banner and once I gave them a fief, their symbols and banners all stayed Red and Yellow which look exactly like Vlandia's colors so I can't tell my Kindoms fiefs from Vlandia's fiefs.

How do I fix this?

I am pretty sure the background of your flag is currently determined by your kingdom culture. I also can't change it. I would also prefer it if I could.
It seems that currently the way it was envisioned is that you first take over the kingdom you were a vassal of: You automatically declare war on that kingdom, the encyclopedia talks about a "civil war" and you choose the culture of an existing kingdom.
At least I had envisioned the kingdom I did found more as a new thing. It was comprised of mostly Vlandian fiefs conquered as a Sturgian vassal, which made it weird to explicitly choose one of the two cultures, and automatically declare war on my former allies instead of becoming an independent but friendly state.