Is that when its the active window?
mine goes like this if its not the active window -
its not as light a grey as yours. I am using a theme though.
Are you using a chrome theme? they can alter the colors -
https://chrome.google.com/webstore/category/themes
Go to chrome settings and click the hamburger menu (3 lines next to settings) and choose appearance, this will show you what theme you are running. reset to default is pretty easy to see from here.
what setting have you got in windows? right click desktop, choose personilisation and then colours.
Is it auto picking a accent color from background?
Under show the accent colour, are the two choices ticked or unticked? Title bars would be the choice that changes it.
Chrome themes over ride the Windows choices, as I had to remove my theme before windows could make the tab bar change color from black.