[Закрытые] Classified Listing gives Error 500 when update on other languages

Background of the issue:
I need to find the reason why we get Error 500 when we make changes in translated project.
Here is the screen recording - скрытая ссылка
Where is shown that when we make changes in Estonian then everything is fine but when we make changes in Russian then we get Error 500. And every time when we get Error 500 we need to delete .htaccess and create new one via Wordpres Settings -> Permalinks.

I contacted theme support and they couldn't find any errors in their theme or plugins. And we contacted server provider support and they said the reason of Error 500 is a lot of redirections and server can't work them all. Can you assist us with that?

Symptoms:
Every time when update translated project get Error 500

Questions:
1. Could be problem in settings of translation?
2. How can we fix it?