Hi there,
Please kindly keep the CSS code which my colleague suggested and also add the Javascript code below to Pro > Launch > Theme Options > JS:
jQuery( function($) {
$(document).on('click', '.vc_tta-tab a', function( e ){
$('html, body').stop();
});
});
The code above will stop the extra scrolling functionality which is happening when tab items are clicked. Now the result is this:

Regarding the Mobile view, unfortunately, we can not do a thing as it is directly related to mobile devices animation rendering capabilities which are limited. Also, we can not change the codebase of Visual Composer and at the moment we only offer it as a bundled extension.
We strongly suggest that you use our Cornerstone product to build your pages to have the most efficient experience on mobile devices as much as those devices rendering capabilities allows us to have a performant code.
Thank you for your understanding.