You must specify the _formTz=<tz> parameter appended to the share URL when initializing a form with date, time or date/time controls from an XML init document, the _data parameter or a business rule that uses the rule identifier,form.load. This is because the form server needs to know the timezone in which to return the date and time. Successful initialization cannot be guaranteed if the &_formTz parameter is not supplied. This URL parameter is not needed if your form/flow only contains date controls. Refer to Time Zones for the details.