Inconsistent behaviour with IMAP rename: Duplicate Messages

[sralpert]

My connection uses IMAP in and SMTP out!

I sent a simple file to myself (in my Tbird inbox):

Checking Spectrum webmail:

Used plugin to edit title:

See that original is not shown, but looking at webmail:

I then moved Test message with edited subject in Tbird to a local folder with drag & drop and refreshed web email: Nothing showed in Tbird inbox but webmail showed BOTH

I then STOPPED and restarted thunderbird. At that point, the messages disappeared from webmail and from Tbird inbox. The messages don't appear in the webmail trash. Were they "erased" when I stopped Tbird?