Saying "me too" isn't really helpful. I'll be glad to look into this 
further if there is any new information provided. At a minimum I would 
need a sync log showing the attempted deletion. Ideally, a FULL sync 
log of a freshly created account showing the initial folder hierarchy 
being synchronized.

also having a similar issue.
I am not able deleting any email from my Android device.

im having a very similar issue but mines with IMP AND ACTIVESYNC

for some reason when i say delete an email, it moves the email to 
trash fine BUT after refresh, it reappears back in the original folder 
AND in the trash also?

and when i check my IMAP server, its just COPIED the email to the 
deleted and not issued the command to MARK DELETE?

our server logs here - https://pastebin.com/sK3Dj3x6
they show the connect in OK, then the UID COPY to copy email which is 
fine then LOGOUT ?

no MARK DELETE?

have i maybe missed a setting somewhere in the my backends.local.php ?

Well, this output looks fine...so it's not likely localization...

  I blocked with the packet filter any other device. So only my cell 
phone (with thee AS accounts on it) shows up in this log

PHP Code

1 var_dump($registry->mail->getSpecialMailboxes());

Ergebnisse

array(6) {
   ["composetemplates"]=>
   object(IMP_Mailbox)#244 (1) {
     ["_mbox":protected]=>
     string(9) "Templates"
   }
   ["drafts"]=>
   object(IMP_Mailbox)#250 (1) {
     ["_mbox":protected]=>
     string(9) "Entwürfe"
   }
   ["sent"]=>
   array(1) {
     [0]=>
     object(IMP_Mailbox)#245 (1) {
       ["_mbox":protected]=>
       string(8) "Gesendet"
     }
   }
   ["spam"]=>
   object(IMP_Mailbox)#241 (1) {
     ["_mbox":protected]=>
     string(4) "Spam"
   }
   ["trash"]=>
   object(IMP_Mailbox)#235 (1) {
     ["_mbox":protected]=>
     string(10) "Papierkorb"
   }
   ["userspecial"]=>
   array(0) {
   }
}


So far looks fine, also Papierkorb aka Trash has no special char like 
Entwürfe/Drafts

The synclog does not show any delete request. I'm not sure what you 
mean by enabling packet filtering for this log, as it's not a 
wiretrace. If you had "Mark as deleted" selected in IMP, then this 
explains why there are no delete requests in the log, as the EAS 
protocol REQUIRES a Trash folder to work correctly.

For deletion to work, IMP must be configured to use a real Trash 
folder, and not just Mark as Deleted. Though, since you say you have 
tried this previously, something else must be going on.

To see if the localization is what is causing the issue, let's start 
by first making sure the you are using a real Trash folder in IMP and 
then executing the following code in the Horde Administrative PHP 
Shell (Gear Icon -> Administration -> PHP Shell) and posting the 
output here.

<code>

var_dump($registry->mail->getSpecialMailboxes());

</code>

Hello,

my ActiveSync clients cannot delete emails. This happens with several 
clients (Nine, BB Hub on Android, iPhone). As unusual feature, I 
localized the the IMAP special folders in dovecot.

Sending EMails is working without problems. The Nine clients has a 
feature "archive" which requieres to define the archive foder. This is 
working, at the moment I use this gimmick to delete mails from my inbox.

The problem is the same with the horde option "mark emails as deleted" 
or move deleted mails to particular folder.

After I delete a email, it needs a few seconds and a refresh, and they 
appear again on the cell phone. Just for the records, the BB hub is 
smart enough, to remember, that this mail was deleted and hides it.

dovecot special folder config:
namespace inbox {
        mailbox "Entwürfe" {
                auto=subscribe
                special_use = \Drafts
        }
        mailbox Spam {
                auto=subscribe
                special_use = \Junk
        }

        mailbox Papierkorb {
                auto=subscribe
                special_use = \Trash
        }

        mailbox Gesendet {
                auto=subscribe
                special_use = \Sent
        }

        # If you have a virtual "All messages" mailbox:
        mailbox virtual/Alle {
                    special_use = \All
        }

                # If you have a virtual "Flagged" mailbox:
        mailbox virtual/Markiert {
                special_use = \Flagged
        }

        mailbox Archiv {
                    auto = subscribe
                            special_use = \Archive
        }

        mailbox Notes {
                auto = subscribe
     }
}


active sync log is here: https://pastebin.com/S2udLbXv
at 11:35:10 it starts with a delete and a few seconds later the 
refresh from the client.
No other user are in this log, I enabled packet filtering before this log.
In this log I used the option "mark deleted in inbox"

Please let me know, if you need more details / logs / whatever.

Thank you