Looks like a bug (see attachment). Actually, it acts like one.

version 4.1.8.1 upgraded from 3.x

If you're community is down I would recommend that you submit a ticket.

Look 7 lines above your marked part

 

	/* Columns */
		if ( is_string( $columns ) )
		{
			$query .= $columns;
		}
		else
		{
			$query .= implode( ', ', array_map( function( $col )
			{
				return ( mb_strpos( $col, '`' ) === FALSE ) ? ( '`' . $col . '`' ) : $col;
			}, $columns ) );
		}

I would suggest to review your settings for the external login handler and to submit a ticket