[Plugin: All-in-One Event Calendar] Events disappear from exported feed

Hi,
First of all, thank you for this great plugin! I use it in the following way:
– I created a “master” Google calendar, from which I import (on an hourly basis) the changes into All-in-One event calendar. This works really well.
– Now, when users subscribe to my AI1EC via the “subscribe in Google Calendar” button, it works … for a few days. But I already noticed twice in the last 2 weeks that all events suddenly disappeared from my (or my followers’) Google Agenda. We had to re-subscribe in order to re-import all entries in Google Agenda.

Could this issue be related to the fact that the export URL changes at every refresh of the calendar page ? The last working URL I was using was (according to Google Agenda):
http://www.harmoniedesion.ch/?plugin=all-in-one-event-calendar&controller=ai1ec_exporter_controller&action=export_events&cb=232890478

and the new one (from today) is :
http://www.harmoniedesion.ch/?plugin=all-in-one-event-calendar&controller=ai1ec_exporter_controller&action=export_events&cb=1634660202

Using the first link indeed now imports a “blank” calendar into Google, which seems to indicate that all events have been flushed out, and that only the second URL works. Do you have any idea why the first URL suddenly became obsolete? I could not find out when (every day? every week?) AI1EC updates its export ics feed, and if this is related to the disappearance of the events.

Possible things that might help troubleshooting: I am using W3 Total Cache (but explicitly not caching the calendar page), and I followed a couple of guidelines found in other topics here in order to strip htmlentities and html tags in the exported feed.

Thank you very much for your support and for this great plugin!

Cyril

http://wordpress.org/extend/plugins/all-in-one-event-calendar/