My coder also checked the problem. Now everything is done.
As the reply from Dokan, the reason is the difference in the version of the plugin Dokan.
Our site (the first site in your video) is the old version of the plugin Dokan. So the Add to cart Product is still the popup style.
On your site (the second site in your video) is the new version of the plugin Dokan. So the Add to Cart is open to the new page (see the attached video below): https://drive.google.com/file/d/1Ei_2SJqnExyrl14H7HMISQeP2wQSMNFe/view?usp=sharing
so there will not have the error as in your video anymore.
=> the problem is that we don't know why there is a mistake between Add to Cart with popup style and Add to cart with opening the new page. He said that he just checked your site and then took the video, but he still did not touch or fix anything on your site.
About the alight the button, he added the CSS in Theme Options: https://prnt.sc/NqGq6fXmomoc
Pls check it and backup the CSS when you change anything or update the theme.
Regards,
Yame