It's partly that. It's basically the game syncing back up to create a fair experience for both players - because it desyncs a bit to allow the pitcher to pitch with no input delay, and the batter to have no input delay while hitting. Fielding and baserunning need to be synced because they're done simultaneously. Usually when this happens for me it's on bat to ball contact, not ball to batter contact. And I haven't seen the ball swerve into a batter, but I have seen it "teleport" to another place in the strike zone (or out of it) while I was batting.
Yeah, I've seen this from time to time too - even pre patch. It wasn't something that was introduced after the patch. Missing a call is one thing, but missing something right down the middle is an obvious bug. Fortunately it only happened once or twice in any given online game that I played - hopefully it's not more frequent now.