I think I may have found a bug in TC 11.03 x64.
Here's how to reproduce:
1. Get two RARs, one password-encrypted, another without encryption (this should be big, with multiple RAR volumes).
2. Allow internal unpack.
3. Start unpacking the one without encryption and click 'Background' once internal unpacking starts.
4. Start unpacking the password-encrypted one, enter the password and click 'Background' once internal unpacking starts.
5. Wait. When the extraction of the one without encryption proceeds to the next volume, TC will prompt for password
