Some of our users are experiencing an issue where calendar entries are created with incorrect participants. Specifically, the listed organiser of such an appointment is not always the user who created the event but rather a random person. Additionally, the incorrect organiser is not always the same but varies and is not necessarily an invited person. Sometimes invites are not sent so that invitees are not aware of the appointment. The occurrence of this effect does not depend to the number of invitees.
Not all of our users face this issue - some calendars work flawlessly.
Calendar entries issued by the Web-GUI are always correct.