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

[PGNet Dev]

On 5/18/22 8:00 AM, PGNet Dev wrote:
> 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?

with Tbird cache(s) DISabled,

	browser.cache.disk.enable = false
	browser.cache.memory.enable = false
	browser.cache.offline.enable = false

this issue continues.

That suggests that this is NOT a TBird cache issue?

Reading,

	https://doc.dovecot.org/configuration_manual/mail_cache_settings/
	https://doc.dovecot.org/settings/core/#core_setting-mail_cache_fields

I suspect these params in Dovecot

	mail_cache_fields =
	mail_always_cache_fields =
	mail_never_cache_fields =
	mail_cache_unaccessed_field_drop =

, which atm for my install are @default values,
may need to be modified.

if so? to what?