As the two crews gather at Lt. Nancy Randolph's bedside, the color of Lt. Comm. Tom Markel's shirt switches from its usual gold to blue when in long-shot.
When the two landing parties are allowed to leave, Kirk directs the Enterprise to beam them up, specifying "all human" to avoid the previous beam up that accidentally grabbed a Latran child. He overlooks that Spock, a part of the party but half-Vulcan, is not all human.
In the transporter room scene, Scott's sleeves bear the two and a half strips of a full captain.
The Lactren child would not be able to fit inside the Enterprise turbo lift to get to the bridge.
The reflections of Kirk, Spock and McCoy in the water is not mirrored. Their "arrowhead" insignia are still on their left when they should appear to be on their right, and none of the rainforest trees behind them appear in the water's reflection, just an open, blue, cloudless sky.
For one shot, Markel and Bryce's "arrowhead" insignia are on the right side of their uniforms instead of the left.
Close-ups of Scott operating the transporter shows his shirt sleeve to lose one stripe and suddenly sporting a mustache. This is obviously a recycled shot of Transport Chief Kyle operating the transporter.
Kirk sanctimoniously posits that "the captain of a ship...must follow the book." The number of times in which Kirk has violated orders, both direct and general, to save the lives of his crew and individual members of it (for example, diverting to Vulcan against orders in Amok Time (1967)) would fill a book in and of themselves.
Although Tom Markel refers to himself as lieutenant commander, he wears the stripes of a full commander.
From the Enterprise, Scott tells Kirk that there's possibly a city to the northeast of his position on the planet, but when the aliens carry Kirk and the landing party to the city, Kirk mentions they've traveled northwest.
Kirk announces to the landing party (Spock and McCoy) that they'll be traveling light, taking only phasers, tricorders, communicators and a medical kit. In other words, the standard stuff. It's unclear if Kirk was making a joke in prefacing it as "traveling light."