Outlook add in (calendar event): Series Id when editing "single event and the following"

Question

I have an Outlook addin for calendar events (Office 365 Web), which has a taskpane to show info for the user.

I have a problem when I edit a recurrence event, "this event and the following".

These are my steps:

I open an event on day_1, and set a 'daily' recurrence for 3 days [day_1, day_2, day_3].

Then I open my taskpane and I can read the id from Office.context.mailbox.item:

  item1_id

and the recurrence info:

   {"recurrenceProperties":{"interval":1},"recurrenceType":"daily","recurrenceTimeZone":{...},"seriesTime":               
            {"startYear":2020,"startMonth":10,"startDay":27,"endYear":2020,"endMonth":10,"endDay":29,"startTimeMinutes":600,"durationMinutes":30}
   }

Then I save the event in the calendar.

A) If I open "all the series" to edit I read from the Office.context.mailbox.item:

• seriesId: null

• itemId: seriesId (=item1_id, saved value when series created --> I know it is my series)

B) If I open a single event to edit, I read:

• seriesId: seriesId (=item1_id, saved value when series created --> I know it is an event from my series)

• itemId: itemB

C) If I open to edit "day_2 and the following", I read:

• seriesId: null (it is correct?)

• itemId: itemC ( I don't know this event is from the series I created...)

My code:

Office.onReady(info => {
    g_item = Office.context.mailbox.item;

    g_itemId = g_item.itemId;
    if (g_itemId === null || g_itemId == undefined) {
        g_item.saveAsync(function (result) {
            g_itemId = result.value;
            g_item.recurrence.getAsync((asyncResult) => {
                if (asyncResult.status !== Office.AsyncResultStatus.Failed) {
                    g_recurrence = asyncResult.value;
                    console.log("Recurrence: " + JSON.stringify(g_recurrence));
                    console.log("ITEM ID: " + g_itemId);
                    console.log("SERIES ID: " + g_item.seriesId);
                }
            });
        });
    }
    else
        console.log("**** itemId found: " + g_itemId);
});

I hope you can understand my problem...

Thanks,

Diego