Emails deleted from Thunderbird Windows (or other apps) appear in K9

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

Thunderbird for Android

App version

9.0

Where did you get the app from?

Google Play

Android version

14

Device model

Samsung A13 5G

Steps to reproduce

1. Open K9. Open any email from the unified inbox. Close K9.
2. From Thunderbird Windows app, delete this email.
3. Open K9. The email deleted still appears. Even if I force the sync.

Expected behavior

For sure, an email deleted from any app, and mainly from Thunderbird Windows, should not appear in K9.

Actual behavior

The email deleted still appears in K9 even if I force the sync.
It seems, like other Android mail apps (i.e. Samsung Email), that emails previously open in K9 but permanently deleted later on, still appear in the inbox. Cache problem or something else?

Logs

No response

Reproduce the issue using Thunderbird Windows and K9's unified inbox on the stated Android setup, then trace what happens when the opened message is deleted externally and K9 is force-synced. Done means a message permanently deleted in Thunderbird no longer remains visible in K9 after synchronization.