Russian translators across the world face the same problems while making their best translation stand out. It is not enough to merely "know" Russian grammar or Russian slang. Even being a native Russian speaker doesn't always make for the best-possible translations between Russian and another language.
The goal for any Russian translator or Russian interpreter is to identify the right cultural feeling so that the intent, not just the word-for-word translation, can be correct. Russian translators should understand the terms and phrases which are appropriate based on the context of the translation - the people and culture(s) involved.
It's also important that an experienced English-Russian interpreter or translator understands the mindset of the people involved in the translation - the words and phrases they will expect and understand.
Russian, as well as every other language, reflects the world view of the people, their behavior, stereotypes. Professional translators and interpreters understand this and apply it to their work accordingly.
Therefore, you can't just learn the Russian language and expect to understand the culture. You need to live in Russia in order to "feel" the Russian language. Every nation has a lot of concepts and unique words and phrases to express them.
For example, concepts for English culture are "sense of humor," "gentleman," "freedom," "home." For the Russian culture they are "soul," "heart," etc.
A professional Russian-English translator or English-Russian translator must get to the heart of the Russian or English language and use the right words and phrases to communicate. This way, the Russian-English translation or English-Russian translation will be adequate for Russian- or English-speaking people.
Very often, so-called Russian-English translators are unable to use these key words and phrases because they belong to a different culture. And, surprisingly, not every native Russian speaker can feel their own language. Only a highly-skilled Russian linguists can make an adequate Russian translation.