Unified inbox widget doesn't show big inbox.

When I installed K-9 and first setup my mail, the widget was showing all mails, as expected.
Then I set the "Local folder size" to "all messages" and "Sync messages from" to "Any time (no limit)".

Expected behavior

All messages shown.

Actual behavior

No messages shown.

When I set a lower limit and reboot the widget works again.

Steps to reproduce

1. have a big inbox (in my case +/- 5000 mails, 300 unread)
2. set the "Local folder size" to "all messages"
3. set "Sync messages from" to "Any time (no limit)"
4. add "Unified inbox widget" to homescreen.

Environment

K-9 Mail version: 5.600

Android version: replicant 6 0003

Account type: IMAP

Please take some time to retrieve logs and attach them here:
My version of adb:
Android Debug Bridge version 1.0.40
Version 4986621
Installed as /nix/store/73zsiynckxkki5xxap7qk7r4laxp1g60-platform-tools-28.0.1/libexec/android-sdk/platform-tools/adb
does not recognize the --pid option.
I was not able to find out how to log just K-9.
Please update the wiki and I'll attach a log.

Start by reproducing the Unified inbox widget with a large IMAP inbox, “Local folder size” set to “all messages,” and “Sync messages from” set to “Any time (no limit). Investigate the widget behavior and obtain K-9 logs using an Android debugging method supported by the reported adb version. Done means the widget displays messages under these settings, including the reported large-inbox case.