Thread:Project:Support desk/1062: Duplicate entry '1' for key 'ss row id' (1.18.1)

Guest visitors of my wiki get 1062: Duplicate entry '1' for key 'ss_row_id' every time site_stat table refreshing (SiteStatsInit::refresh). Login user do not see this error, and if I put ?action=purge to main page all be okay. File cache is turn on. Please, help!

My db looks like: CREATE TABLE IF NOT EXISTS `site_stats` ( `ss_row_id` int(8) unsigned NOT NULL,  `ss_total_views` bigint(20) unsigned DEFAULT '0',  `ss_total_edits` bigint(20) unsigned DEFAULT '0',  `ss_good_articles` bigint(20) unsigned DEFAULT '0',  `ss_total_pages` bigint(20) DEFAULT '-1',  `ss_users` bigint(20) DEFAULT '-1',  `ss_active_users` bigint(20) DEFAULT '-1',  `ss_admins` int(10) DEFAULT '-1',  `ss_images` int(10) DEFAULT '0',  UNIQUE KEY `ss_row_id` (`ss_row_id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8;

INSERT INTO `site_stats` (`ss_row_id`, `ss_total_views`, `ss_total_edits`, `ss_good_articles`, `ss_total_pages`, `ss_users`, `ss_active_users`, `ss_admins`, `ss_images`) VALUES (1, 50, 11920, 1134, 2816, 314, -1, -1, 829);