wrong time when making invitation from iCal to windows outlook

Hi,

We have problem with iCal invitations from iMac, iPhone and iCloud to windows outlook. Windows user gets invitation from apple devices with correct time in message text, but when they add event in their calendar, there is one hour time lag, one hour more than it should be. We have tried from many devices and different iCloud accounts. Our regional settings are set to EEST time zone (Riga, Latvia). In summer we have day light saving and we set our clocks +1 hour, that means we have the same time as Moscow. If I change time zones to MSK - Moscow time, there is no problem with wrong event times on microsoft outlook.

There is no problem between apple devices. Can you help us? Highly likely there is global problem with our time zone, but it disappears whet we turn back our time.