RRULE recurrence loses DTSTART/server timezone

[Duanxueda]

Description

After applying an RRULE to an existing reminder, the scheduled time changes unexpectedly.

Server timezone

Asia/Tokyo

Steps to reproduce

1. Create a reminder:

/remind target:@everyone time:2026-07-31 22:00 message:SHOP!!

2. Confirm that /reminder_list shows:

31.Jul 22:00

3. Edit the interval and set:

FREQ=MONTHLY;BYSETPOS=-1;BYDAY=SU,MO,TU,WE,TH,FR,SA

Expected

The reminder should remain scheduled for:

31.Jul 22:00

and then repeat on the last day of every month at the same time.

Actual

After applying the RRULE:

• /reminder_list shows:

31.Jul 13:00

• Reminder Info shows:

Due date:
2026-07-31 00:00

The recurrence rule itself appears to be applied, but both the scheduled time and the due date no longer match the original reminder time.

Is this expected behavior?