dovecot - May 2022 - Message attachments, relocated with Tbird in Dovecot maildir store, not openable; reversible by moving BACK to inbox?

> I see same symptoms when opening a mail in thunderbird 2 or 3 weeks after I
received it, without moving it in another folder.
> Burt using "repair folder" in TB, I get it back, so for me it
looks more like a TB cache problem.
hm.  'repair' here does nothing for me.


looking at my current TBird settings for disk/cache/offline/subscription,

	browser.cache.check_doc_frequency,              1
	browser.cache.compression_level,              0
	browser.cache.disk.capacity,              0
	browser.cache.disk.enable,              false
	browser.cache.disk.max_entry_size,              51200
	browser.cache.disk.smart_size.enabled,              false
	browser.cache.disk.smart_size.first_run,              false
	browser.cache.disk.smart_size.use_old_max,              true
	browser.cache.disk_cache_ssl,              false
	browser.cache.memory.enable,              false
	browser.cache.memory.max_entry_size,              5120
	browser.cache.offline.capacity,              512000
	browser.cache.offline.enable,              true

	mail.server.default.offline_download,              false
	mail.server.default.autosync_offline_stores,              false
	offline.download.download_messages,              2
	mailnews.offline_sync_mail,              false
	mailnews.offline_sync_news,              false
	mailnews.offline_sync_send_unsent,              false
	mailnews.offline_sync_work_offline,              false
	offline.autoDetect,              false
	offline.send.unsent_messages,              2
	offline.startup_state,              0


	mail.server.default.check_all_folders_for_new,              true
	mail.check_all_imap_folders_for_new,              true
	mail.imap.hide_unused_namespaces,              false
	mail.imap.auto_unsubscribe_from_noselect_folders,              false
	mail.server.default.using_subscription,              false
	mail.imap.hide_unused_namespaces,              false
	mail.server.default.override_namespaces,              true

i _thought_ that^^ should eliminate local caching.

sounds like, perhaps, i've misconfigured, or am missing, something ...

4/1/22
> I see same symptoms when opening a mail in thunderbird 2 or 3 weeks after I
received it, without moving it in another folder.
> But using "repair folder" in TB, I get it back, so for me it
looks more like a TB cache problem.
I've still not managed to solve for this problem; 'repair'
doesn't fix it.

Anyone here have a reliable fix -- either on the TBird &/or Dovecot sides --
to get these subfoldered attachments openable/readable?
Ideally without the need for manual intervention each time?

The issue, again is:

Email with attachments (e.g., pdf) I receive to an account INBOX can be accessed
in TBird/Linux with no problems.

Dubl-Click on the attachment, and it opens in app -- e.g. pdfs open in Okular.

Saving the attachment to Desktop,

	ls -al /home/pgnd/Desktop/SomeFile.pdf
		-rw-r--r-- 1 pgnd pgnd 197K May 18 07:49 /home/pgnd/Desktop/SomeFile.pdf

All good.

If I move the message , including attachment, to any other (sub)folder, and try
to open the attahment,

I get the usual open dialog,

	You have chose to open:

	SomeFile.pdf
	which is: Portable Document Format (PDF) (66.7 KB)
	from: imap://mx.example.com:993

	What should Thunderbird do with this file?
	[X] Open with 'Okular (default)'

which, on 'OK', does open Okular -- with an Error:

	Error -- Okular
	Could not open file:///tmp/pid-59993/SomeFile.pdf

checking

	ls -altr /tmp/pid-59993/SomeFile.pdf
		-r--------+ 1 pgnd pgnd   27 May 18 07:46 'SomeFile.pdf'

If I move the message BACK to imap INBOX, and open/save attachment it's good
again.

Thunderbird is not correctly retrieving the attachment when the message is not
in imap:INBOX.