Emails in sub-folder not all appearing/syncing

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

6.707

Where did you get the app from?

Google Play

Android version

11

Device model

LG G7

Steps to reproduce

Greetings, I've noticed that the emails in a sub-folder are not all appearing on K-9 Mail. When I open the folder in Thunderbird or the webmail, it shows 52 but when I open it on K-9 Mail, there's only two(2) showing.

1. Tap the top left "hamburger" (3 horizontal bars) icon
2. Select the email you want. (for me the email address with the sub-folder mentioned is already the default email, so I can just hit the subfolder)
3. If the email with the sub-folder you want to look at is not in the default email address, tap the email/name at the top, and then tap the email you want to switch to
4. Tap the "hamburger" icon again and then the sub-folder you want to look in.

By the way, the Sent folder on K-9 Mail is not syncing the emails sent with Thunderbird or other email client/webmail.

Thank you.

Expected behavior

The same emails on K-9 Mail that I have on the webmail and other email client such as Thunderbird.

Actual behavior

It's not loading the other emails, there's only two emails/threads showing on K-9 Mail.

Logs

k9-debug-log.txt

Start with the attached k9-debug-log.txt and reproduce the sub-folder and Sent-folder sync behavior on the reported Android 11 and K-9 Mail 6.707 setup. Compare the folder contents with Thunderbird or webmail; done means all 52 sub-folder messages and sent messages appear in K-9 Mail.