First of all I would like to thank you for testing.
However, the problem occurs when you switch to mobile, tablet or any other view within WP Page bakery excluding desktop view on the frontend editor. The same thing happens when you decrease the window size on any browser such as Google Chrome & Safari.

Please find the attached video showing you where the error occurs.

Window Browser: https://gyazo.com/b66ff9bc9b2d09315246851ed3a638cd
Front end visual composer: https://gyazo.com/8c47463cc4d0b25675f8474fc16ddf95