Here is an example which demostrates the problem:

root@s484:/home/vpopmail/domains/jaro.user# vadduser pma@jaro.user

root@s484:/home/vpopmail/domains/jaro.user# ls -la
...
drwx------  3 vpopmail jaro   4096 Jan 14 05:43 pma
drwx------  3 vpopmail jaro   4096 Oct 28 06:09 postmaster

root@s484:/home/vpopmail/domains/jaro.user# vdeluser pma@jaro.user

root@s484:/home/vpopmail/domains/jaro.user# ls -la
...
-rw-------  1 root     root      4 Jan 14 05:44 .dir_control_free
-rw-------  1 root     root      0 Jan 14 05:44 .dir_control_free.lock

root@s484:/home/vpopmail/domains/jaro.user# cat .dir_control_free
pma

root@s484:/home/vpopmail/domains/jaro.user# vadduser test123@jaro.user

root@s484:/home/vpopmail/domains/jaro.user# grep test123 vpasswd
test123:xxx:1:0:test123:/home/vpopmail/domains/jaro.user/pma/test123:NOQUOTA:1

root@s484:/home/vpopmail/domains/jaro.user# ls -la pma/
total 12
drwx------ 3 vpopmail jaro 4096 Jan 14 05:44 .
drwx------ 4 vpopmail jaro 4096 Jan 14 05:44 ..
drwx------ 3 vpopmail jaro 4096 Jan 14 05:44 test123

The expected storage directory for the mailbox "test123" is "/home/vpopmail/domains/jaro.user/test123", not "/home/vpopmail/domains/jaro.user/pma/test123"