Symptoms

The "6 Jan, 2015" is doubled in calendar control in Google Chrome, Firefox and old versions of IE (prior to version 10)
 

Diagnoses

This is known issue which appears after installation of the update for Russian time zones from Microsoft (September 2014 time zone update for Russia - http://support.microsoft.com/kb/2998527), on servers with Russian time zone set. This issue with calendar control appears in Chrome, Firefox and IE9 only (newer versions of IE work fine). Therefore if you have this update and your time zone on K2 server which hosts SmartForms is set to Russia, Moscow you will see this behavior.
 

Resolution

K2, Microsoft and affected browsers developers aware about this problem. Appropriate fix for this problem is expected from Microsoft. As for now Microsoft is researching this problem and will post more information when it becomes available. A new update from Microsoft is expected that will update the .NET Framework to correctly use UTC offsets and adjustment rules for all time zones.