Canceled Events of Series Events hidden while single events stay visible

[LukasMino]

Checklist

• I can reproduce the bug with the latest version given here.
• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one bug.
• I have read and understood the contribution guidelines.

Affected app version

1.10.3

Affected Android/Custom ROM version

Android 15/ eOS 4.2

Affected device model

Fairphone 5

How did you install the app?

F-Droid / IzzyOnDroid

Which calendar service or provider do you use, if any?

mailbox.org

Which sync adapter app do you use for calendar synchronization, if any?

DAVx5

Steps to reproduce the bug

Case A:

1. Create a series event
2. Mark one of the series events as canceled

OR
Case B:

1. Create a series event somewhere else (I tested it in Thunderbird on my PC and the web app of my calender service)
2. Mark one of the series events as canceled on there

Expected behavior

The series event is shown as canceled just like with single events

Actual behavior

Case A:
The event gets deleted everywhere.

Case B:
The event cannot be seen in the fossify calender anymore (locally deleted?) but is still exists everywhere else.

Screenshots/Screen recordings

No response

Additional information

I have seen this issue here and I am not completly sure if this is related as it is not about series events:
#482

(I do not think so, as this is a Fossify-specific issue (not on other apps) and it only effect series events, not single events.)

[LukasMino]

I now found out this creates even more problems:
If I follow Case B with a 2-event-series I end up with a single event in fossify. If I now delete this event in the fossify app, it will onyl be deleted on there. Everywhere else it is still shown as a series with one canceled and one normal event.

I assume Case B creates some sort of desynchronisation between the service and the fossify calender and this will create most likely even more bugs. Unfortunatly, I also get not error messages about this.