Incorrect handling of DST for reoccurring events

[freezingDaniel]

Checklist

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

Affected app version

1.0.2

Affected Android/Custom ROM version

Android 13&14

Affected device model

Tab S6 Lite

How did you install the app?

F-Droid / IzzyOnDroid

Steps to reproduce the bug

1. Set Device TZ/clock to UTC+0
2. Set Device Date to 2024-03-25 (not sure if necessary)
3. Calendar settings: Events>Allow chaing event time zones
4. Create Events
   1. Create daily reoccuring event for 3 days at 2am & 3am with Timezone Berlin from 2024-03-30 to 2024-04-01
   2. (optional) repeat with different calendar app

Expected behavior

On 2023-03-26 in the morning in Germany (at 2am German/eventTZ) the clock is set to an hour forward to (to 3am) DST

• 2024-03-30 events stay the same
• 2024-03-31 events (2am&3am) should overlap
• 2024-04-01 events should be moved accordingly

Samsung Calendar:

Actual behavior

• events are shown incorrectly

Screenshots/Screen recordings

see above

Additional information

It has been a while since I originally encountered this issue (by missing an important appointment) but it was the reason I (unfortunately) had to stop using this Calendar.

While I have not verified this time, for my old issue I came to the conclusion:

• A recurring event that's created while being in CET, is incorrectly displayed once in CEST (ics file is correct)
• A recurring event that's created while being in CEST, is correctly displayed in CEST (ics file is correct)

Maybe related to: Issue-166

Potentially useful in case I missed something: https://github.com/SimpleMobileTools/Simple-Calendar/issues/1973