What should be the behaviour when completing a recurring task that already has a Done date?

[claremacrae]

I just discovered that completing this:

- [ ] Wibble 🔁 every day 📅 2022-07-07 ✅ 2022-07-02

gives:

- [ ] Wibble 🔁 every day 📅 2022-07-08 ✅ 2022-07-02
- [x] Wibble 🔁 every day 📅 2022-07-07 ✅ 2022-07-02

This is in Tasks 1.8.2.

I was presuming that the Done date would be removed from the duplicate task, as it's kind of an error to have a Done date on an incomplete task.

I'm not sure that I care enough to do anything about it...

Especially as it is now possible to write searches to find such tasks:

```tasks
not done
has done date
```

But wanted to capture the observation for now anyway.

[AnnaKornfeldSimpson]

Per the docs on recurring tasks (and also my experience using recurring tasks), other date fields in recurring tasks advance relative to the due date when the recurring task is regenerated. It confuses me that the done date appears AND that relative date advance isn't happening with the done date.
I don't have a strong opinion on the "right answer" (removing the done date seems fine) but I don't like that the current behavior contradicts my understanding of the docs.

[claremacrae]

That’s a great point. Thank you.