Programmatic control in between timezone offset results in shedule next day

[SamLue]

Local Summer Time is UTC+2 (timezone = "Europe/Berlin")

For Example:
Actual Time is 2025-06-09T07:48:07.162Z which is 09:48:07 local time.

If I try to set the on- or offtime programmatically shedex schedule the event for next day, even it is in the future.

let datetime = new Date("2025-06-09T07:48:07.162Z");
shedexOnTime = new Date(datetime.getTime() + 1 * 60 * 60 * 1000); //1 Hour in the Future

msg.payload = {};
msg.payload.ontime = shedexOnTime.toISOString();
msg.payload.onpayload = "on"
...

This results in 2025-06-10T08:48:07.162Z and not on the same day in 1 hour.
If I use a time 121 minutes in the furture, which is 1 minute more than the timezone offset, everything works as expected und it is planned for same day.

[SamLue]

OK,

maybe the problem is, that the property payload.ontime and .offtime can not handle a date-Object ISO-String correct with an local time offset.

In the documention I found the example für msg.payload.ontime: 12:00
With the description: Time as specified in the table above for time configuration

If I use the local time in this Format "HH:mm" everything works fine.

In case of using ISO-String e.g. "2025-06-09T07:48:07.162Z" schedex schedules the "07:48" as local time and not UTC-Time.