When on mobile the tabs in k2 show the content of tabs just fine (no tabs headers show)
for Easyblog it shows tab headers, if one clicks on it nothing happens unless you refresh. But all content for other tabs do no show at all.
Sorry, but I told you what is the issue.
You have been in the Joomla game long enough to know that not all extensions play well together.
You can't expect me to solve the issues on your website caused by other extensions.
Sorry if the tone came across too harsh. But message is the same.
You have a lot (too much) going on on those web pages with extensions loading multiple versions of Bootstrap styles and scripts.
Tabs relies on Bootstrap (which comes with Joomla core). So if you have other extensions loading their own versions of Bootstrap all together, then there comes a point where stuff stops working well.
It is the way it is and I can't fix that for you.
You need to see what combination of stuff is breaking and make choices which parts are most important to you.
Seeing Tabs is just for presentation, not for functionality, I guess that in most cases the choice will be to find a different solution to Tabs.