Deficiencies with Calendar; this time with repetitive events

You have created a repeating event. When you make a change and choose "Save for This Event Only", the change you make is only for that event. It is still a repeating event as you initially set it up and the only change is going to be the modifications you made to that single event. If you want the change you make to be reflected in your future events it will be if you choose "Save for Future Events". I just verified the behavior again by changing the Time and Notes of an event and saved it for that event only. All other events appear exactly how I initially set up the repeating event.

Ok, I think I understand. You are looking for some indication that an altered event has been changed, whether that is with a grey repeat message or maybe even an additional notation stating that the repeating event has been altered for that particalar event. In that case I think the provided Feedback link is the way to go.

The event is still going to be a repeating event no matter if it was edited or not. For example, if I create a repeating event that says to "Take Medication" and it is daily at 8:00, then on one day I change it to 9:00, it does not change the fact that "Take Medication" is a daily event.

Your memory has not failed you where previously the Repeat message did disappear when an event was edited, but I also think that is confusing because the event was still a repeating event. That is verified when you would go to delete/edit the event and it still asks you if you want to delete/edit Future events even though it is no longer labeled as repeating. I could only suspect that users were confused why an event that was not labeled as repeating is asking to delete Future events and they also sent Feedback seeking clarification.

Your suggestion for some additional visual cue that a repeating event has been altered would satisfy the confusion for both cases, so would suggest also using the Feedback link.

Feedback - Calendar - Apple

For now I would stick with using Feedback for the feature request you identified to provide some visual notification on when a repeated event is edited. That is a clear feature that makes sense and should be understandable. As for listening to your feedback, you can be assured it will be read and most likely logged. Apple will consider requested enhancements, although as you could imagine, there must be some kind of criteria such as the number of users who have made a request or the significance of the feedback that will have some bearing. You should not expect any kind of communication on the progress of your submitted feedback.

As for your other complaints, I would suspect it could be some kind of bug although I have not seen it myself on my end. We can dig into those a little deeper if you can gather some screenshots or are able to figure out the exact sequence of events that would cause a repeating event to duplicate itself. It may be best to start a new post once that information is gathered and I would be happy to test/verify on my end in an attempt to determine the cause.

When I change a repeating event, I am given the option to "Save for this event only" or "Save for future events". For me it works exactly as expected where if I change a repeating event to a different day and choose "Save for this event only", that is exactly what it does and the previous repeating events remain unchanged. The event I change is moved to the different day and repeating is no longer an option.

Are you perhaps using a Google account, such as gmail, that is syncing with your Calendar app? The Calendar I am using is the iCloud calendar.

Feel free to provide feedback at apple.com/feedback. I cannot recall the note of "repeated event" ever going away after making a change to one event.

I cannot recreate your issue. Changing one instance of a repeating event does not change the others.