True! One of the most terrible cont errors I've ever seen is where they slipped in a shot of a a klingon and expected the audience wouldn't notice it WASN'T Saavik.
Damn! I completely forgot about this!
Yeah, it's just before the Pon Farr scene. At one stage I speculated that this was intentional, as if a Klingon had gone ahead and was trying to sneak up on Saavik and Spock, only to get killed during the tectonic event.