They've done a good job of containing them this season. But the cable/TV providers (last week AT&T, this week Amazon Prime) have fucked up by releasing it a few hours early. It's debatable whether or not these were "mistakes", but because I don't smoke weed and like to get shit done I'm not gonna spend the next 4 hours reading too far into conspiracy theories.
Still nothing compared to last season though, when the main plot points were leaked. Apparently there were no paper scripts issued to anyone during filming. All issued scripts were digital, on restricted iPads (no screenshots, only available during filming).