When sorting WP_List_Table, table sorts, but I also get SQL errors

the part ORDER BY $orderby $order LIMIT get translated to ORDER BY asc LIMIT, the columnname that supose to be in $orderby is missing, and there for the sql fail.

looks like you want your default value to be ‘title’

$orderby = (isset($_REQUEST['orderby']) && in_array($_REQUEST['orderby'], array_keys($this->get_sortable_columns()))) ? $_REQUEST['orderby'] : 'title';

may geuss is that in_array() return true even when $_REQUEST[‘orderby’] is empty,
and therefor accepting a empty $_REQUEST[‘orderby’] insted of ‘title’.

if you add this row, dose the error messages diseper? (under $orderby, above $this->items)

$orderby = $orderby :? 'title';