(2.4.5) (web-mobile) seems 3D contents scale fit automatically on the browser for the height, but not the width?

At 2.4.5, if I mix 2D canvas with 3D content and build with web-mobile and run at browser, the 2D content can scale with the browser window size for both width and height, but for 3D content, it seems just don’t scale with width, is it true?

So, there is a project with a 3D box on a 2D canvas:

When build with web-mobile and run on browser, when the height of the window is adjusted, both the 2D canvas and 3D box looks scaling correctly:

However, when the width is adjusted, it seems only the 2D canvas is scaled but not the 3D box (see the box would cover the ‘eye’ of the logo because the logo is scaled down but not the 3D box):

So I want the 3D contents scale as if the 2D contents on the screen for both width and height, but now it seems not, is it the bug of the engine, or I need other settings for the content of the 3D camera?