[Решено] the translation of some of my FAQ documents in Betterdocs are not applied

Background of the issue:
I have translated all FAQ's in Betterdocs on my site скрытая ссылка.

Symptoms:
For some of the FAQ documents, the translation is not applied and gives an error.

Questions:
Why are some of my FAQ translations in Betterdocs not being applied?
What could be causing the error in the translation application?