Yes, ok, that helps but only for a single page load. As soon as wordpress is called, that transient is back in the table and polylang is broken again.
mysql> select * from t_options where option_name="_transient_pll_languages_list";
| option_id | option_name | option_value | autoload |
| 3748 | _transient_pll_languages_list | a:2:{i:0;O:12:"PLL_Language":17:{s:7:"term_id";i:2;s:4:"name";s:7:"English";s:4:"slug";s:2:"en";s:10:"term_group";s:2:"10";s:16:"term_taxonomy_id";i:2;s:8:"taxonomy";s:8:"language";s:11:"description";s:5:"en_US";s:6:"parent";s:1:"0";s:5:"count";i:165;s:10:"tl_term_id";i:3;s:19:"tl_term_taxonomy_id";i:3;s:8:"tl_count";i:504;s:6:"locale";R:9;s:6:"is_rtl";s:1:"0";s:5:"mo_id";s:1:"6";s:10:"search_url";s:21:"https://127.0.0.5/en/";s:8:"home_url";s:21:"https://127.0.0.5/en/";}i:1;O:12:"PLL_Language":17:{s:7:"term_id";i:4;s:4:"name";s:14:"Русский";s:4:"slug";s:2:"ru";s:10:"term_group";s:2:"20";s:16:"term_taxonomy_id";i:4;s:8:"taxonomy";s:8:"language";s:11:"description";s:5:"ru_RU";s:6:"parent";s:1:"0";s:5:"count";i:94;s:10:"tl_term_id";i:5;s:19:"tl_term_taxonomy_id";i:5;s:8:"tl_count";i:116;s:6:"locale";R:26;s:6:"is_rtl";s:1:"0";s:5:"mo_id";s:1:"7";s:10:"search_url";s:21:"https://127.0.0.5/ru/";s:8:"home_url";s:21:"https://127.0.0.5/ru/";}} | yes |