I have upgraded my client's site to Joomla 3.9.2 and K2 to 2.9. After doing so the frontend editing panel will not close. It did however work when on old K2 and pop up window. We have very limited components of which we have updated. Our issue is with the old way of doing things with the popup and everything works, now with this new way it doesn't. We noticed that the black border around the pop up edit screen in the new version is not there. Our template is a very simple Joomla template so there are no extra js files anywhere. We opened a Javascript error panel, but there are no errors that we can see.

We would like some help in fixing this.

new.douglasglengardens.ca/

Sorry no, it did not resolve the issue.

Ok, I figured out what you guys did. You changed the code on the edit link. I had html overrides for pages
you use to have this:

<a class="modal" rel="{handler:'iframe',size:{x:990,y:550}}" href="<?php echo $this->item->editLink; ?>">
<?php echo JText::_('K2_EDIT_ITEM'); ?>
</a>

Now you have this:

<a data-k2-modal="edit" href="<?php echo $this->item->editLink; ?>">
<?php echo JText::_('K2_EDIT_ITEM'); ?>
</a>

After changing the edit link on my pages it works.