First event of recurring series disappears on every uneven edit

[dantefromhell]

Problem

The first event of a recurring series disappears every 2 edits, starting with the first edit, than it re-appears after the 2nd edit and disappears on the 3rd edit.

It does not seem to be a UI display problem, as reloading the calendar view does not re-display the missing event. Only editing the event does.

Steps to reproduce

1. From the month Calendar view create a new event, fill in title and set recurrence to weekly and End to never. My first event was 4days ahead of today - the 19th of May.
2. Edit the event by clicking the first date of the event series and select Edit all Events. Make a change to the event series, e.g. adding 'Edit Allow invite participants to event #1 to the description' and hit 'Save'
3. Observe the first event of the series has disappeared from the Calendar
4. Reload the Calendar view in the Browser and find the first date still missing
5. Select the second date of the event series, select Edit all Events. Make a change to the event series, e.g. adding 'Edit New German Translations #2 to the description' and hit 'Save'
6. Observer the first event of the series re-appearing in the Calendar view.
7. Reload the Calendar view in the Browser and find the first event displayed.

I can continuously reproduce disappearance and re-appearance by following steps 2 - 7.
It makes no difference if the first or second in the series is selected in step 2)

The behaviour was not reproducable when editing the third event in the series for the uneven edit. But I'm not sure if this is related to it being the third event in the series or the first event in the series that happens in the next month.

[yurabakhtin]

@dantefromhell Thank you for the report and for the detailed steps of the reproducing!
Fixed in PR #308 and will be in next release.