Lt. Charlene Masters does not wear her Lieutenant stripe.
In a shot of the viewscreen near the end of the episode you can see the planet but there's no stars in the background.
When Kirk escorts Lazarus to the bridge, there's a shot of McCoy as they leave and two Red Alert panels - one is flashing while the other one is burnt out.
The commodore says the distortion was felt in every quadrant of the galaxy and beyond. How does he know this? It takes weeks for messages to get
back and forth (see "Balance of Terror") and how would he know what's going on outside the galaxy?
Despite the fact there's a warning of an alien invasion and Lazarus is at the center of things, not to mention kind of wacko, he wanders freely around the Enterprise.
Starfleet sends out a code factor 1 command - everyone is to go on alert status because of a possible alien invasion. Then the commodore asks Kirk's opinion on what's going on and Kirk says it's an alien invasion.
The Lazarus who has a beard has it keep appearing and disappearing throughout his scenes.