If you are using the 1.x compatible plugin with elgg 2.x then for the above case, you can add these line in your start.php file at line 175

if ($page_owner instanceof \ElggSite) {
 return null;
}

The problem sounded familiar. Check my comments at https://elgg.org/plugins/2380396/releases/1.0.0 as these seemed to have worked to fix the issue(s) in the past.

The version I have is from the github page, it was mentioned in the thread about elgg 3.0 rc2 being released......someone needs to do a little better job  doicumenting this stuff.  If there's a fix, then why isn't ithe plugin updated???  I have no idea if the github version is the 1x version or not.  Why don't I know?  Because it comes with zero documentation.