As I noticed an automation did not stop after the duration set in trigger, I start to wonder why. Only thing I did was adding new automations during that time.
Is it true that a duration is reset/gone when editing/saving a new automation during the time the automation with the duration was started? Hope you know what I mean?
yes, if you restart HA or reload automations, including saving automations created/edited with the UI editor since that will auto reload automations too, then any automation currently running (with or without a time delay active) will be aborted.
For future reference it mentions it at the bottom of this section in the second warning. It also mentions an alternative solution using an input_datetime if this is an issue for you.