Audio problem: After Kronos One is fired upon, Kirk calls down to engineering to ask if they had been firing torpedoes. Scotty responds by looking at the inventory screen and saying "Negative Captain. According to inventory we're still fully loaded." That Scotty sure is fast. He gets through saying "Negative Captain" before his reflection even starts moving its mouth. It's a little dark so turn up the brightness on your screen. (00:28:50)
Audio problem: When Kirk and McCoy enter the underground penal colony, Kirk is confronted by a large beast speaking an alien language. Watch McCoy's mouth when he says, "He's definitely on about something, Jim." His mouth doesn't start moving until the camera shot changes halfway through the sentence. (00:59:45)
Audio problem: When Spock mind melds with Valeris, you hear a heartbeat. Whose heartbeat is this? It is specifically stated in the original series that Vulcan hearts beat almost twice as fast as humans. It is, however, never established that Vulcan metabolic functions slow during a mind meld, due to conscious physical control or otherwise.