I have multiple email accounts configured in Thunderbird, all of them are IMAP and hosted through Google/gmail. Occasionally emails that I delete or move to folders will return to my inbox. This happens very irregularly. Sometimes it happens daily, sometimes it can go many days without an occurrence. If emails are sorted within the gmail browser interface, the problem never happens. I've tried a complete deletion of Thunderbird and all app data, and resetting all email accounts but the problem persists. Thanks in advance!