This happens because you have Thunderbird to save drafts periodically. Each save becomes a separate draft. A possible workaround is to set your draft folder to use local storage.

Thanks. I guess that is better it is just that I would of preferred the ability to continue to edit a saved draft on my phone in the mail app on the phone if I am away from my desktop. At least now I do not have all the saved copies in TB after I send the email.

(Thunderbird 115.3.1 64bit, Windows 10) Had the same issue and found a workaround in the bugtracker: https://bugzilla.mozilla.org/show_bug.cgi?id=549274#c35 where it says one should not point email drafts and templates to the same folder but two distinct ones instead. I initially changed it to point both to the same drafts folder but that caused the problem. After resetting the folders to distinct ones Thunderbird handles saving email drafts and deleting them after sending the email perfectly fine again. It's just a pity that this bug seems to exist for over 14 years...