Thunderbird keeps creating multiple draft messages for each save. I can start composing an email, hit Ctl-s to save and I get an unread message in Drafts. If I hit Ctl-s to save again (or TB autosaves, it doesn't matter) I get yet another unread message in Drafts. This just builds up crud which needs to be manually deleted. I am using IMAP and like the functionality where if I saved a draft on my desktop, I could pick it up on my laptop later.

Thunderbird 91.3.1 Email server: Postfix 3.3.0 Dovecot 2.2.33.2 on Ubuntu 18.04