There is one linguistic subtlety associated with the presence of cases in the Russian language. 

'Lincoln Memorial' in Russian, it will be written as 'Мемориал ЛинкольнУ'. Memorial is not written, so only 'ЛинкольнУ' remains.

In the case of this monument, the ending of the name (Nicholas -> Nicholas) was not written by agreement, yes. But you shouldn't have deleted it.

But in the case of https://osm.org/node/4898059105 everything is correct