Google Chrome is very popular because it actively tries to hide bugs. One of the latest bugs affecting the platform is the problem of missing scroll bars. This is due to users complaining that the scroll bar is not displayed or has simply disappeared from the screen. This can be annoying because you don’t know how many times you have to scroll to the end of the page.
You also can’t click and drag the scroll bar up or down, but that’s not a serious problem. You can always use the mouse wheel or the arrow keys on the keyboard to scroll. However, this spoils the experience a bit. In my opinion, you should fix the error before it gets out of hand or causes other damage.