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

[PGNet Dev]

On 5/18/22 9:51 AM, Virgo Pärna wrote:
>> 	ls -al manual_13542AE.pdf
>> 		-rw-r--r--   1 pgnd pgnd   27 Apr  1 06:01  manual_13542AE.pdf
> 
> 	Try enabling memory cache and setting memory cache size larger,
> then attachment size. That 27 byte file size is familiar.

in Tbird, I set

   browser.cache.memory.enable         true
   browser.cache.memory.capacity       512000
   browser.cache.memory.max_entry_size 51200


, restarted and ... my attachments now open correctly in any/all subfolders.

not what i expected; i'm not at all clear _why_ ENanbling cache solves this problem.
glad that it does, though.

cheers!