The scene is where the astronauts are talking to ground control about HAL’s erratic behavior.
The astronauts are somewhere near Jupiter and ground control is on Earth so the minimum communication transit time is 35 minutes. If they were true to science, the communication would near to impossible, so did Kubrick cheat and use instantaneous communication?
No cheating. They are not interacting just receiving messages.
Edit 1 Another recorded message. Birthday greetings for Frank. (And thanks to the youtube uploaders.)
Edit 2 The news interview Keith Morrison describes in his comment to this answer – which he points out the BBC reporter mentions the time lag.
Edit 3 regarding real deep space communication. The Voyager probes are outside of the solar system now and are sending a 23 watt signal. A cellphone uses 3 watts. So I think a manned spaceship would certainly put power into the communications. Hopefully the AI doesn’t sabotage it. See https://science.howstuffworks.com/question431.htm