If I dismiss a future reminder because I know i'm not going to need that particular reminder (for example, if i have weekly doctor appointments and the doctor cancels that week (or i do) due to travel or other reasons), I should be able to dismiss just that one individual reminder without dismissing all prior reminders.
The way this should work, similar to how it used to work when i first signed up: That reminder gets dismissed, the rest stay. If there are no additional pending prior reminders, then the next occurence date should be moved forward. If there are additional pending prior reminders, the next date should remain unchanged.
I don't remember an idea post suggesting that deleting a reminder should delete all prior reminders, so it is unclear who asked for that feature when it changed.