I cannot find mention of this issue anywhere else, so please ignore if this is a duplicate anywhere.

The problem is that the default widgets don't seem to be holding their values when a checkbox is selected within an elementor enabled page.

To recreate this simply drag a default WP widget such as the Archive widget into Elementor on a page. Check 'Display as dropdown' and save the page. The actual widget behaves as expected. However, upon saving and refreshing the 'Display as dropdown' checkbox will revert back to unchecked even though the widget shows its checked setting in the editor.

I'm testing in the latest version of Google Chrome on OSX with MAMP.