Password field bug - AIR 3.1

I think I found a bug in AIR 3.1. when running on an iPhone. Sequence of events:

1. Add 2 text field to movie clip
2. Set one to type to password
3. Publish to iPhone
4. On iPhone enter data in password field using iPhone text input - text appears as *** (which is fine)
5. Focus on non-password field and the *** displayed in the password field dissappear
6. Change (2) to a none password field and it works fine

Is there a way around this?

Leon