I wasn't able to reproduce this issue, so far. We can wait for our developers to have a deeper look into this issue.
Or, alternatively, you can try following the instructions to clean up your preferences and check if the issue still persists:
Same here this a few weeks. Update PF yesterday to newest 8.3.3. Mail app ist Apple Mail from Mojave 10.14 (german) - no E-Mail and no compress and E-Mail works. It feels that absolut nothing happened. There also is nothing shown in the Apple Activity app