Another point about Soviet scientists: it was very often a career-ending move to accept a Nobel prize unless you were a truly untouchable cult of personality and/or direct friend of those in power. See Andrey Sakharov, who first invented the soviet hydrogen bomb and later dedicated himself to non-proliferation which earned him a Nobel Peace prize. He was however barred from traveling to Oslo to accept in 1975, having already been blacklisted from classified work since 1968.
I wonder to what extent that lead to the curbing of consideration of those behind the iron curtain.
Peace prizes are different from science prizes. The Soviet Union had no problems with its scientists getting science prizes. It did sometimes had problems with letting them leave the country to actually receive them, of course.
While your disambiguation is valid, they very much wanted to minimize the potential fallout from individuals staying in, say, a Norwegian hotel and sampling the local culture only to return and speak fondly of said trip "beyond the curtain". Usually this was outweighed by the national prestige (and subsequent propaganda opportunity) from having a Soviet Nobel recepient but the KGB had an extremely heavy hand in deciding who got to go, regardless of scientific breakthrough.
I wonder to what extent that lead to the curbing of consideration of those behind the iron curtain.