Sometimes strange behavior may be caused by a plugin or theme conflict. The fastest way to rule out conflicts is to deactivate all non-Yoast plugins and switch to a standard theme like Twenty Seventeen. If this resolves the issue, you have a conflict and should activate one plugin at a time until you locate the conflict. Finally, after all plugins are active, switch to your theme. This will narrow down the conflict to a specific plugin or theme.
If you are unfamiliar with checking for conflicts, we wrote a small guide that will walk you through the steps. You can find it here: How To Check For Plugin Conflicts
Thread Starter
rulik
(@rulik)
Hi
I switched to Twenty Sixteen theme:

Activated only Yoast SEO:

But the issue still remain:

That is strange. Do you see any errors in your browser’s console?
How to find JavaScript errors with your browser’s console?
The errors imply that JavaScript is not enabled or enabled too late. If you disable only the Yoast plugin, do you see similar errors about undefined jquery?
Thread Starter
rulik
(@rulik)
I reinstalled WordPress and issue disappeared 🙂