This question already has an answer here:
The astronauts on the International Space Station have a daily schedule, particularly when they are asleep versus awake. Which Earth time zone is closest to their daily schedule?
What time zone is used on ISS to define a day? asks a similar question. Three answers state that time is referenced by UTC. That's not what I'm asking. There is one answer relevant to my question, but it is not the accepted answer, so I'm not sure whether it is an accurate answer. Also, @PearsonArtPhoto made a comment there that this issue should be asked as a separate question.
Also somewhat related, but not directly answering the question: What kind of time regime/schedule do ISS astronauts have?
It is my understanding that the Canadarm2 can be remotely operated from Earth, and that it is often done so while the astronauts are sleeping. In that case, it would make sense to have the astronauts awake when it is daytime in Moscow, so the robotics can be done when it is daytime in the U.S./Canada.