This is not a technical bug per se, but just reporting a wrong use of historical resources. As far as I can see, Turkish logo is star and crescent with a green background, which is historically inaccurate. Green flag is the colour of the Islamic Caliphate, and historically used to symbolise Islam, not Turkish civilisation. Here are some suggestions:
- If the in-game civilisation is supposed to portray Ottoman Empire, the background should be red! If you want to use the coat-of-arms, see here, for flag examples see here.
- If you want to prefer a more general Turkic image, the colour you want to use is turquoise. For the symbol you can use, wolf head, two-headed-eagle, or the tree-of-life. These are all prominent symbols from the Turkic mythology.
Feel free to ask for more information, will be happy to provide.