it's a question of who is making the copy, not the copy per se. Ukranian copies (what most folk call russian) are made, especially during the 60s and 70s, by people paid by the piece, not for quality, and in a culture where you check everything you buy for the date of manufacture because everything made on monday is made by people fighting hangovers and on friday by people looking to get off work early.
Even the stuff made on Wednesday was definitely a "Quality is job Two" proposition.
The wonder is that any of the things work, a testament to their good design.
With the Kiev 35mm cameras the earlier ones were made by workers trained by Germans and they're usually better. Later models are more iffy as the dies for the parts got older, things were redesigned to be cheaper and newer more poorly trained workers took over.
And don't even get me started on the Kiev 88 ...