Thunderbird Mail Synchronisation

Subject: Thunderbird Mail Synchronisation
Provider: A1 Account (Austria)
E-Mail Address Format: IMAP
Thunderbird Release: 115.08.0 (32-Bit), Updated standard download
Operating System: Windows 10

Problem description:

1. When a received e-mail is moved from the TB Inbox to the TB Trash Folder of the A1 account, then the mail disappears on the A1 server account and on the smartphone (Samsung E-Mail).
   
2. When a received e-mail is moved from the TB Inbox to one of the TB Local Subfolders, then the mail still remains on the A1 server account and on the smartphone
   
   
3. Only in case the A1 server account is called up (mailbox is empty!) and closed again then the e-mail disappears on the A1 server account and on the smartphone as well.
   
   

It looks like Thunderbird does not send a synchronisation request for the now empty TB inbox after the mail move to a Local TB Subfolder. Only in case the A1 Web Account is called up then the account activates a synchronisation cycle with Thunderbird recognizing the empty TB Inbox.

Is my assumption correct and if yes, could you provide a solution or do you have another idea for problem analysis/repair?

Best Regards
Larry

I have no impact caused by filter rules or addons detected. Yesterday I detected a new processing mode: "After closing TB the rewsidual moved mails disappear from the Smartphone E-Maibox" after few seconds. It looks that TB sends a synch with the now empty Mail In-Box to the smartphone during the closing cycle.

I have no idea why the new processing mode is now in place. Maybe I have changed something when I tested
possible Addon and Filter problem sources.

Regards Larry