Tabs are bouncing when you click on them (in joomla articles).
Soon as I unpublished K2 system plugin bouncing stopped.

Checked source code in one of the article pages and saw that it is k2.js file is opening in every article.

Checked and found lines:
// Smooth Scroll
new SmoothScroll({
duration: 500
});

Uncommented them and Magic Tabs worked fine afterwards.
Maybe will help someone with similar problems and conflicts.

Actually it is not a bug. They just dont work together with smoothscrool in K2 activated.
I had to uncomment similar lines in my template js file to get them work.

Hi. I assume that this is a javascript conflict. If the extension you mentioned is using jQuery then it might has to be set in no conflict mode.

It is fixed now. Core Design scripts come with new jQuery js files.