Another experience here, sadly. Apparently PearsonVUE still hasn't learned to handle this. I used "Take a break" functionality during my exam today. Shortly after returning proctor bluntly told me that leaving during exam is not allowed. I immediately typed in chat that it IS allowed as this is Microsoft exam and I did exactly as instructed, but I was thrown out regardless. I then spent about 40 minutes in phone trying to reach PearsonVUE support, got a ticket number and now waiting for them to get back on my case. No idea how long that will take, I'm really angry at the moment having prepared and reserved time for the exam. I also just reported this to Microsoft on aka.ms/mcpforum.
For the time being I recommend everyone NOT to take breaks in Microsoft exams, even though it is allowed by Microsoft you don't want to risk PearsonVUE screwing up your exam. Really sorry this is still the case after all this time.