After migrating dovecot Linux/2.0.9 mail database in form of Maildirs to FreeBSD/2.3.20 and forcing doveadm force-recync on mail database I'm still getting the old reported to be fixed crash:

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Feb 14 17:12:10 it-r-support dovecot[5888]: auth-worker(6378): Debug: mysql(localhost): Finished query 'SELECT maildir, 1143 AS uid, 1143 AS gid FROM mailbox WHERE username = 'zheganin-em@alamics.ru' AND active = '1'' in 0 msecs
Feb 14 17:12:10 it-r-support dovecot[5888]: auth-worker(6378): Debug: conn unix:auth-worker (uid=143): auth-worker<16>: sql(zheganin-em@alamics.ru,192.168.57.177,<oE2zjKn0FTXAqDmx>): Finished userdb lookup
Feb 14 17:12:10 it-r-support dovecot[5888]: auth-worker(6378): Debug: conn unix:auth-worker (uid=143): auth-worker<16>: Finished
Feb 14 17:12:10 it-r-support dovecot[5888]: auth: Debug: sql(zheganin-em@alamics.ru,192.168.57.177,<oE2zjKn0FTXAqDmx>): Finished userdb lookup
Feb 14 17:12:10 it-r-support dovecot[5888]: auth: Debug: master userdb out: USER        1282408449      zheganin-em@alamics.ru  maildir=alamics.ru/zheganin-em/ uid=1143        gid=1143        auth_mech=PLAIN auth_token=15cceab95e1251ea97a8e5ff62c70d1b7a76c96f
Feb 14 17:12:10 it-r-support dovecot[5888]: imap-login: Login: user=<zheganin-em@alamics.ru>, method=PLAIN, rip=192.168.57.177, lip=172.16.11.13, mpid=6405, session=<oE2zjKn0FTXAqDmx>
Feb 14 17:12:10 it-r-support dovecot[5888]: imap(zheganin-em@alamics.ru)<6405><oE2zjKn0FTXAqDmx>: Panic: file array.c: line 10 (array_idx_modifiable_i): assertion failed: (idx < array->buffer->used / array->element_size)
Feb 14 17:12:10 it-r-support dovecot[5888]: imap(zheganin-em@alamics.ru)<6405><oE2zjKn0FTXAqDmx>: Fatal: master: service(imap): child 6405 killed with signal 6 (core dumped)
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Backtrace:

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# lldb /usr/local/libexec/dovecot/imap --core imap-6404.core 
(lldb) target create "/usr/local/libexec/dovecot/imap" --core "imap-6404.core"
Core file '/var/cores/imap-6404.core' (x86_64) was loaded.
(lldb) bt
* thread #1, name = 'imap', stop reason = signal SIGABRT
  * frame #0: 0x000000001151133a libc.so.7`__sys_thr_kill + 10
    frame #1: 0x0000000011489c74 libc.so.7`__raise + 52
    frame #2: 0x000000001153b109 libc.so.7`abort + 73
    frame #3: 0x000000001137a336 libdovecot.so.0`___lldb_unnamed_symbol5855 + 150
    frame #4: 0x0000000011378ad1 libdovecot.so.0`___lldb_unnamed_symbol5844 + 49
    frame #5: 0x0000000011379881 libdovecot.so.0`___lldb_unnamed_symbol5846 + 33
    frame #6: 0x0000000011378ceb libdovecot.so.0`i_panic + 187
    frame #7: 0x000000001136a514 libdovecot.so.0`array_idx_modifiable_i + 100
    frame #8: 0x0000000012054a78 lib20_fts_plugin.so`fts_user_autoindex_exclude + 72
    frame #9: 0x0000000012051b3b lib20_fts_plugin.so`fts_mailbox_allocated + 267
    frame #10: 0x000000001113ad0b libdovecot-storage.so.0`hook_mailbox_allocated + 155
    frame #11: 0x0000000011134491 libdovecot-storage.so.0`mailbox_alloc + 449
    frame #12: 0x0000000001044311 imap`cmd_select_full + 353
    frame #13: 0x000000000104cd92 imap`command_exec + 178
    frame #14: 0x000000000104b64a imap`___lldb_unnamed_symbol1265 + 58
    frame #15: 0x000000000104b7b6 imap`___lldb_unnamed_symbol1265 + 422
    frame #16: 0x000000000104a151 imap`client_handle_input + 465
    frame #17: 0x00000000010488a8 imap`client_input + 120
    frame #18: 0x00000000113936df libdovecot.so.0`io_loop_call_io + 111
    frame #19: 0x0000000011396214 libdovecot.so.0`io_loop_handler_run_internal + 388
    frame #20: 0x0000000011393dea libdovecot.so.0`io_loop_handler_run + 378
    frame #21: 0x0000000011393c28 libdovecot.so.0`io_loop_run + 88
    frame #22: 0x00000000112f6208 libdovecot.so.0`master_service_run + 24
    frame #23: 0x000000000105af67 imap`main + 1383
    frame #24: 0x000000000103c11d imap`_start + 269
(lldb)
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