That's still the legacy voice flow plugged on top of the new model. OpenAI has announced as such and it's very different than how the demos for the yet to be actually launched new voice mode work.

this is really a common misconception mostly caused due to confusing UI in the app. See https://simonwillison.net/2024/May/15/chatgpt-in-4o-mode/

Can you interrupt it with voice?