When running the attached file and then changing the system timezone, it takes two calls to Date.timeZoneUpdated() for the Text component to show the date in the new timezone. After the first one, only the timezone is updated.

This also affects "new Date().getTimezoneOffset()" - our application displays a list of locations and allows the user to select from these to set the timezone, then displaying the UTC offset. The effect in this case is that the displayed offset lags by one selection (corresponding to a call to Date.timeZoneUpdated()).