My Russian friends say that no one says "nazdrovye" when drinking together, but it's in all the films. Why?

I've heard numerous times that the stereotype stemms from the fact that during the cold-war period Russians were commonly played by other slavs in American movies. Among them were the Polish, who allegedly say "Na zdrowie" when they drink. So at some point things got mixed up.

I'm not sure if it is a valid explanation, but it does sound legit