Thank for contacting us and reporting this issue to us!
I have tested the mentioned demo and the issue is present only in Safari.
We have made a work item for this and we will work on to fixing it.
Please, do not hesitate to contact us if you have any additional questions.
Smart UI Team https://www.htmlelements.com/
We investigated the item, but we are still unable to find a solution for it. It is related to the smart-tabs component with specific sizes in auto-hide mode only. Once the issue is resolved, the information will be published in the release notes section on our website.