Modifying weekly event occurrence is causing error message

I am using eM Client 7.1.31849.0 against Microsoft Exchange 2016 using EWS. If I create a recurring weekly appointment that occurs on Tuesday and Friday (for example at 8am), then try to change the appointment time for a specific Tuesday (not the first one, but the second or others), then I get the error below. Editing just the subject also produces an error:  

10:54:03 AM   MailClient.Storage.Application.ItemOperationException: Modified occurrence is crossing or overlapping adjacent occurrence., Modified occurrence (StartTime: 13/03/2018 1:00:00 AM, EndTime: 15/03/2018 9:30:00 PM) is crossing or overlapping an adjacent occurrence (StartTime: 13/03/2018 9:00:00 PM, EndTime 13/03/2018 9:30:00 PM).

Changing the time of a Friday instance does not give me an error. From the logs it appears eM Client is doing a GetItem on InstanceIndex of 4 (for example), when I edit instance 3. Editing instance 4 does correctly request InstanceIndex 4.

Hello Peter,

Send me please an email to with a link to this thread and a version of eM Client you’re using.

Thank you.