Old meeting updates/changes being sent out multiple times to meeting invitees

[ilc168]

I sync outlook 365 desktop with my hosted email services calendar.

I had a recurring meeting that I cancelled on 6th Sept. On a sync event, the cancellation was sent again today 19th Sept. This has happened before. I can't reproduce. I can't explain why some old changes are sent multiple times and some are not. It may have something to do with time zone changes and updates to outlook?

Noting, this has happened with other non-recurring meetings, with meeting invitees receiving old cancellations or old meeting updates, sometimes several times.

For now, I've updated the sync to be from outlook --> server (replicate). Previously it was outlook <--> server (merge). Unsure if this will help or not.

Any advice?