Hi,
Banner is changing fine when I checked in demo site. It may be due to catch please clear the catch and check again. There is another solution to change the banner height. You can set height of banner height using css code. Add following code snippet to set the height in additional css section in customizer.
.cir-banner {
height: 40px;
}
If doesnot solve your problem please send us your site url so that we can give you exact solution.
Thanks
