Very annoying in the sense that this issue has been around for quite awhile however my memories of the circumstances have faded quite effectively. So no good clues, only some possible crumbs.
If I remember correctly I used to have similar issue with Android phone in around 2018. I had to use an app to delete the multiplied Outlook365 calendars from the phone. I have vague recollection that especially with subscribed calendars there was an issue in the sense that if I got rid of them on the phone and in Outlook (webUI) there could still be some remnants synced to the phone from the server. Never managed to find a solution for that before the Android phone broke but this made me think that this might be some stupid server stuff rather than a client thing.
Anyways, I started using X2 in March 2019 (then switched to 10 III in the summer 2022) and I now have 17 copies of the same calendars. This does somewhat align with O365:s 90 days reauthorization period as I used iPhone for a bit and there was that Oauth issue. This is to say only if the reauthorization does happen every 90 days with the Sailfish’s account connection as well…can’t even remember that accurately, but at least every now and then one needs to reauthorize the account in Sailfish nevertheless. Maybe a factor?
However I digged into the calendar database and there are some interesting dates related to one of my calendar and its copies:
syncDate modifiedDate createdDate
2023-07-13 02:08:51 2023-07-13 02:08:52 2023-01-31 23:57:29
1970-01-01 00:00:00 2023-07-16 14:35:21 2023-07-16 14:35:12
2023-07-20 00:45:36 2023-07-20 00:45:37 2023-07-16 19:51:28
2023-08-04 17:35:16 2023-08-04 17:35:17 2023-07-24 08:25:53
2023-08-17 05:57:37 2023-08-17 05:57:37 2023-08-13 21:36:22
2023-10-24 17:01:47 2023-10-24 17:01:50 2023-08-24 16:51:22
2023-12-03 08:39:27 2023-12-03 08:39:28 2023-11-11 13:02:59
2023-12-14 10:49:01 2023-12-14 10:49:06 2023-12-14 10:48:38
2023-12-22 01:08:27 2023-12-22 01:08:28 2023-12-19 06:31:06
2024-01-07 13:25:13 2024-01-07 13:25:13 2024-01-07 12:25:47
1970-01-01 00:00:00 2024-01-11 00:34:18 2024-01-11 00:34:09
1970-01-01 00:00:00 2024-01-18 13:17:38 2024-01-18 13:17:30
1970-01-01 00:00:00 2024-01-18 13:34:04 2024-01-18 13:33:54
2024-04-01 22:40:17 2024-04-01 22:40:18 2024-01-27 08:56:54
2024-04-05 13:52:36 2024-04-05 13:52:37 2024-04-02 05:08:08
2024-04-13 00:47:25 2024-04-13 00:47:25 2024-04-06 22:38:21
2024-04-30 13:16:09 2024-04-30 13:16:09 2024-04-13 07:52:07
(this last one has the latest/current calendar entries)
These creation dates are of course nonsense in the sense afaik the multiplication issue did not start in 2023-07-16 14:35:12. And if the dates are taken as a fact, they do not of course fit with the 90 day reauthorization cycle. However I’m 99% confident that I had to 17 copies of the same calendar about a month ago as I do now despite what the createdDate tells.
In comparison to these dates another calendar, a subscribed one, had pretty much the same creation dates with an possible offset of 1 or 2 seconds, otherwise didn’t see any other coinciding things.
I’ll try to monitor to see if there’s any interesting changes happening.
Edited for clarity