This is manifested as:

– the user enters credentials for authorization in e-mail or other services where authorization is required

– at other user’s workplaces also a login/password is begun to enter, for example, in a text document or text field

The problem is created by Kaspersky Anti-Virus – the function is called “Secure Data Entry” and is used to protect against keyloggers. Duplication of input occurs because the antivirus intercepts the input before JoinCloud, when it is not yet divided into workplaces and directs all in the browser window, bypassing everything. You can solve the problem only by disabling the “Safe Data Entry” feature in the antivirus settings. Deselect all (or part of) checkboxes in Settings → Advanced → Safe data entry in Kaspersky Anti-Virus settings. Sites on which the “Safe Data Entry” function should not work can be added to the exclusion list.