Bug in Serv-U 15.1.2? - Expired Password Change not working

Good Morning,

Having upgraded 2 Serv-U servers at the weekend to 15.1.2.189, users can no longer change their password when it expires. A server running 15.0.1 is still fine.

Scenario -

1.    A user has the checkbox "user must change password at next logon" ticked, making their password expire immediately.

2.    User attempts to login

3.    Enters their current and new passwords

4.    The following error is shown..

A closer inspection using Firebug shows a 401 Unauthorized error..

Is anyone else experiencing this?

Thanks in advance,

Chris