Sent items duplicated

Checklist

• I have used the search function to see if someone else has already submitted the same bug report.
• I will describe the problem with as much detail as possible.

App

K-9 Mail

App version

11.0

Where did you get the app from?

F-Droid

Android version

13

Device model

Fairphone 3

Steps to reproduce

• Send email (with outlook.com account, not tested with others)
• Note that sent folder contains 2 copies of the email when viewed through outlook.com (only contains a single message when viewed through K9)

Expected behavior

A single copy

Actual behavior

Android (only one entry):

outlook.com (two entries):

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Sometimes the emails are direct duplicates (so far as I can see), but sometimes the to field is different - on the second email it gets replaced with something of this format: outlook_986188D25A21AC9A@outlook.com (which is annoying if I come back to it, reply all to that message to continue the converstion, and then get a "could not be delivered" message from outlook).

Logs

k9mail-logs (1).txt

Start by reproducing the issue with an Outlook.com account on Android 13, then inspect the attached k9mail-logs (1).txt while comparing the sent folder in K-9 Mail and Outlook.com. Done means sending one message results in one sent copy and does not replace the recipient with an undeliverable Outlook address.