Was able to duplicate your issue. Appears related to CBuser usage. Not quite sure why its doing this though. Only resolution appears to remove such usage, but that of course will break the plugin. Have not experienced this with other integrations as typically formatname field is used. The following block of code is resulting in the display.
[code:1]
$cbUser = CBuser::getInstance( $lastview->viewer_id );
$name = $cbUser->getField( 'name', null, 'html', 'none', 'list' );
$username = $cbUser->getField( 'username', null, 'html', 'none', 'list' );
$avatar = $cbUser->getField( 'avatar', null, 'html', 'none', 'list' );
[/code:1]
Seams to be related to CBs API and its caching of the cbuser object. Have created a bug ticket for further investigation.
forge.joomlapolis.com/issues/2166