swipe to next message crashes back to folder message list when multiple newest unread mails with same timestamp in thread

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 version

6.603

Where did you get the app from?

F-Droid

Android version

14 (One UI 6.0)

Device model

No response

Steps to reproduce

1. Go to a folder with a single mail next to a thread, whose two messages have the exact same timestamp and are unread (e.g. Gitea sends those double mails on closing an issue with comment).
2. Open the single mail
3. swipe sideways to the thread

Expected behavior

One of the two newest mails in thread opens and is marked as read

Actual behavior

One of the two newest mails shortly (½ second or so) shows up, then the UI suddenly switches back to the message list of that folder. The message that blinked up is marked as read.

Logs

k9mail-logs.txt

Start by reproducing the folder-to-thread swipe using two newest unread messages with identical timestamps, then inspect the attached k9mail-logs.txt for the transition back to the message list. The fix is complete when swiping opens one of the newest messages, marks it read, and keeps the thread view open.