Hi Joe-
That background gets generated based on the color palette, but since the text color has been changed manually we’ll need to use a little custom CSS to fix it.
Navigate to Customize > Advanced > Custom JS & CSS and use the Custom Theme CSS field.
If you want to completely remove the background, use code similar to this:
.palette-primary .call-to-action-wrapper { background-color: unset !important; }
I’d recommend actually changing it to a semi-transparent black background, like this:
.palette-primary .call-to-action-wrapper { background-color: rgba( 0, 0, 0, 0.5) !important; }
Which will look like this: