https://www.imdb.com/name/nm0752923 - this name seems to be simply copied from the 'kinopoisk', but corresponds to no real person, as further explained.
According to the profile, 'O. Ryazanov' is an actor who played in
Privet, duralei! (1996) - Russian movie, and
Tini zabutykh predkiv (1964) - Soviet-Ukrainian movie.
In fact, we have no such name listed as an actor anywhere, except 'О. Рязанов' at the https://www.kinopoisk.ru/name/196094/ . If we search for the same name in another Russian database, there are no similar results https://www.kino-teatr.ru/search/22317568/576201/ . And the name is not mentioned on the movie-pages: https://www.kino-teatr.ru/kino/movie/5615/titr/ ; https://www.kino-teatr.ru/kino/movie/sov/7117/titr/ .
Moreover, kinopoisk has no more links to any names that could be not exactly the same but similar https://www.kinopoisk.ru/s/type/people/list/1/find/%F0%FF%E7%E0%ED%EE%E2/ - there are no 'Олег Рязанов', or 'Остап Рязанов', or else starting with 'О'. So, only one short name for only two movies. I've re-watched both movies trying to find the phatom person who'd be young enough in 1964 and old enough in 1996 to participate in both as an actor. Noone matched.
It is closer to truth that O. Ryazanov in 'Privet, duralei!' must be 'Э. Рязанов' (E. Ryazanov) - the short name of Eldar Ryazanov himself, as printed in titles backdropped (https://www.imdb.com/title/tt0117392/mediaviewer/rm832467968).
For the old famous 'Tini zabutykh predkiv' we have incorrect duplicate of existing actor Aleksandr Raydanov. His Ukrainian name 'Oleksandr Raydanov' printed as short 'О. Райданов' (O. Raydanov) in titles. This movie includes no actor named Ryazanov - not credited, nor uncredited one.
According to the profile, 'O. Ryazanov' is an actor who played in
Privet, duralei! (1996) - Russian movie, and
Tini zabutykh predkiv (1964) - Soviet-Ukrainian movie.
In fact, we have no such name listed as an actor anywhere, except 'О. Рязанов' at the https://www.kinopoisk.ru/name/196094/ . If we search for the same name in another Russian database, there are no similar results https://www.kino-teatr.ru/search/22317568/576201/ . And the name is not mentioned on the movie-pages: https://www.kino-teatr.ru/kino/movie/5615/titr/ ; https://www.kino-teatr.ru/kino/movie/sov/7117/titr/ .
Moreover, kinopoisk has no more links to any names that could be not exactly the same but similar https://www.kinopoisk.ru/s/type/people/list/1/find/%F0%FF%E7%E0%ED%EE%E2/ - there are no 'Олег Рязанов', or 'Остап Рязанов', or else starting with 'О'. So, only one short name for only two movies. I've re-watched both movies trying to find the phatom person who'd be young enough in 1964 and old enough in 1996 to participate in both as an actor. Noone matched.
It is closer to truth that O. Ryazanov in 'Privet, duralei!' must be 'Э. Рязанов' (E. Ryazanov) - the short name of Eldar Ryazanov himself, as printed in titles backdropped (https://www.imdb.com/title/tt0117392/mediaviewer/rm832467968).
For the old famous 'Tini zabutykh predkiv' we have incorrect duplicate of existing actor Aleksandr Raydanov. His Ukrainian name 'Oleksandr Raydanov' printed as short 'О. Райданов' (O. Raydanov) in titles. This movie includes no actor named Ryazanov - not credited, nor uncredited one.




MAthePA
If the future advice is to spend efforts and time on editing one-two-plenty of wrong credits when they link to virtual/unreal entities. If you mean it, thank you as well.
Vincent Fournols