Interesting, is this after running an additional tellmail resync?

Can you send me the output of :
    tellmail status
from both systems.

And then try this:
    tellmail resync_user john@wilkes.com

Let it finish, then check those folders again, is the problem gone?

    ChrisP.,

In every case it looks like the size reported by “du” is smaller on the mirror. Some examples:

on the server:

180772K	/var/surgemail/wilkes.com/va/wb/john/mdir/2016%2e07-09
193284K	/var/surgemail/wilkes.com/va/wb/john/mdir/2016%2e10-12
279688K	/var/surgemail/wilkes.com/va/wb/john/mdir/2017%2e01-03
148552K	/var/surgemail/wilkes.com/va/wb/john/mdir/2017%2e04-06

on the mirror:

151540K	/var/surgemail/wilkes.com/va/wb/john/mdir/2016%2e07-09
144000K	/var/surgemail/wilkes.com/va/wb/john/mdir/2016%2e10-12
156480K	/var/surgemail/wilkes.com/va/wb/john/mdir/2017%2e01-03
110876K	/var/surgemail/wilkes.com/va/wb/john/mdir/2017%2e04-06

Looking at one of those directories, /var/surgemail/wilkes.com/va/wb/john/mdir/2016%2e07-09, there are more files on the server than on the mirror:

server: ls -1 /var/surgemail/wilkes.com/va/wb/john/mdir/2016%2e07-09 | wc -l
3643

mirror: ls -1 /var/surgemail/wilkes.com/va/wb/john/mdir/2016%2e07-09 | wc -l
3383

Here is part of a context diff of the output of “ls -1” from mirror and server:

$ diff -c ls-1-mirror.out ls-1-mail.out
*** ls-1-mirror.out 2017-12-04 21:23:35.775993890 -0800
--- ls-1-mail.out       2017-12-04 21:24:31.109474252 -0800
***************
*** 11,16 ****
--- 11,17 ----
  u1009~2,S(0,1888)[1467415418]
  u1010~2,S(0,66783)[1467444553]
  u1011~2,S(0,65102)[1467450827]
+ u1012~2,S(0,34034)[1467463028]
  u101~2,S(0,87675)[1467877535]
  u1013~2,S(0,63565)[1467464861]
  u1014~2,S(0,67470)[1467489698]
***************
*** 29,34 ****
--- 30,36 ----
  u1026~2,S(0,97501)[1467667206]
  u1027~2,S(0,56112)[1467684236]
  u1028~2,S(0,3675)[1467697203]
+ u1029~2,S(0,103202)[1467724783]
  u10~2,S(0,109174)[1467406715]
  u1030~2,S(0,60523)[1467731066]
  u1031~2,S(0,33183)[1467733985]
***************

Only the mirror is missing files; there are no files on the mirror that do not appear on the server. The directory in the output above is old archived mail, and is static; i.e. no changes were made on the server or the mirror while gathering this information. The “extra” files on the server are legitimate messages which should have been sent to the mirror.

I am running SurgeMail version 7.3c3-3 on both server and mirror. The mirror is a fresh installation (after a disk crash on the previous mirror hardware). The server has been running SurgeMail for many years and has been upgraded several times, most recently from version 6.3c to 7.3c-3 a few months ago.