When Chambers is shooting the commercial for the Vodka, the director stops him for mispronouncing a word that he hadn't even uttered yet. The director corrects his pronunciation of "Chabrim" when the last word Chambers says before being cut was Champion.
When George and Yuri first meet in prison, after George spills water on Yuri's face he tries to trip him with a bench. There is a low angle shot of Yuri coming up to the bench and kicking through it. On the next high-angle shot of the kick George is nowhere to be seen, whereas he should be within feet of the bench.
Stevie is seen injecting drugs after George and Yuri's training sequence. Letting alone the fact that his arm has unbelievably good veins for someone who has been shooting for years, and the fact he appears to inject retrogradely into muscle rather than vein there is in addition a revealing prop: he pushes the needle about 3cm into his arm and then pulls it away revealing that the needle is now 3cm shorter. In a prop like this the needle pushes into the syringe giving the illusion that it goes into the body. Normally the needle is spring-loaded so that it pushes back out, but this did not occur with this prop.