Dragging messages from the inbox to folders in the left panel often doesn't work. The application doesn't respond to dragging at all, although the destination folder is highlighted with a blue rectangle on the left. If you drag several messages at once, then almost always the transfer is performed only for some messages.
The application does not report in any way that the transfer could not be completed.
Also, empty lines often appear in the inbox. Thunderbird has suffered from this since the earliest versions.
