Thank you for reporting a bug to Unity.
After reviewing the behavior, we've confirmed it aligns with the current design and intended use of the feature. We understand this may differ from your expectations or workflow.
This is not a bug, this is by design. Once in Rec mode, clicking the Rec button again toggles between Rec & Preview modes. When in Preview mode, click the Preview button again toggles between Preview and disabled state. You can exiting the Rec mode directly by clicking the Preview button in Rec mode.
We will close this case as 'As Designed.' If you have feedback on how the feature could better meet your needs, please let us know - we value your input and consider it in future improvements.