An email came to several users but one user didn't receive it and we got 'Mail delivery failed' message.

As I see from the log below, there were broken index file.
Then dovecot repaired that index and we got the error:
Panic: file mail-index-sync-update.c: line 1013 (mail_index_sync_map): assertion failed: (map->hdr.indexid == index->indexid || map->hdr.indexid == 0)

It was one-time error and it has not reappeared yet.
At the moment the user receives emails successfully  (in .Queue.A_Sup.group_05 as well).

It is supposed that Dovecot had to repair index file and put the email in mnt/mail//user05/Maildir/.Queue.A_Sup.group_05/ directory but it didn't.
Is there something wrong with Dovecot?

Thanks.

---
Operating system: Linux Centos 7   3.10.0-862.3.2.el7.x86_64 #1 SMP Mon May 21 23:36:36 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

rpm -qa |grep dovecot
dovecot-pigeonhole-2.2.10-8.el7.x86_64
dovecot-2.2.10-8.el7.x86_64

dovecot.log output
---------------------
Aug 06 23:19:24 lda: Debug: Loading modules from directory: /usr/lib64/dovecot
Aug 06 23:19:24 lda: Debug: Module loaded: /usr/lib64/dovecot/lib90_sieve_plugin.so
Aug 06 23:19:24 lda(user05): Debug: Effective uid=10492, gid=10001, home=/mnt/mail/user05
Aug 06 23:19:24 lda(user05): Debug: Namespace inbox: type=private, prefix=, sep=, inbox=yes, hidden=no, list=yes, subscriptions=yes location=maildir:/mnt/mail//user05/Maildir:INBOX=/mnt/mail//user05/Maildir
Aug 06 23:19:24 lda(user05): Debug: maildir++: root=/mnt/mail//user05/Maildir, index=, indexpvt=, control=, inbox=/mnt/mail//user05/Maildir, alt=
Aug 06 23:19:24 lda(user05): Debug: userdb lookup skipped, username taken from USER environment
Aug 06 23:19:24 lda(user05): Debug: none: root=, index=, indexpvt=, control=, inbox=, alt=
Aug 06 23:19:24 lda(user05): Debug: Destination address: user05@imap.po.com (source: user@hostname)
Aug 06 23:19:24 lda(user05): Debug: sieve: Pigeonhole version 0.4.2 initializing
Aug 06 23:19:24 lda(user05): Debug: sieve: include: sieve_global_dir is not set; it is currently not possible to include `:global' scripts.
Aug 06 23:19:24 lda(user05): Debug: sieve: executed before user's personal Sieve script(1): /etc/dovecot/sieve/before/priority_colors.sieve
Aug 06 23:19:24 lda(user05): Debug: sieve: using the following location for user's Sieve script: /mnt/mail//user05/.dovecot.sieve;name=main script
Aug 06 23:19:24 lda(user05): Debug: sieve: executed after user's Sieve script(3): /etc/dovecot/sieve/after/spam.sieve
Aug 06 23:19:24 lda(user05): Debug: sieve: opening script 1 of 3 from /etc/dovecot/sieve/before/priority_colors.sieve
Aug 06 23:19:24 lda(user05): Debug: sieve: loading script /etc/dovecot/sieve/before/priority_colors.sieve
Aug 06 23:19:24 lda(user05): Debug: sieve: script binary /etc/dovecot/sieve/before/priority_colors.svbin successfully loaded
Aug 06 23:19:24 lda(user05): Debug: sieve: binary save: not saving binary /etc/dovecot/sieve/before/priority_colors.svbin, because it is already stored
Aug 06 23:19:24 lda(user05): Debug: sieve: executing script from /etc/dovecot/sieve/before/priority_colors.svbin
Aug 06 23:19:24 lda(user05): Debug: sieve: opening script 2 of 3 from /mnt/mail//user05/.dovecot.sieve;name=main script
Aug 06 23:19:24 lda(user05): Debug: sieve: loading script /mnt/mail//user05/.dovecot.sieve;name=main script
Aug 06 23:19:24 lda(user05): Debug: sieve: script binary /mnt/mail//user05/.dovecot.svbin successfully loaded
Aug 06 23:19:24 lda(user05): Debug: sieve: binary save: not saving binary /mnt/mail//user05/.dovecot.svbin, because it is already stored
Aug 06 23:19:24 lda(user05): Debug: sieve: executing script from /mnt/mail//user05/.dovecot.svbin
Aug 06 23:19:24 lda(user05): Error: Index file /mnt/mail//user05/Maildir/.Queue.A_Sup.group_05/dovecot.index: indexid changed: 1533501509 -> 1464071305
Aug 06 23:19:24 lda(user05): Error: Corrupted transaction log file /mnt/mail//user05/Maildir/.Queue.A_Sup.group_05/dovecot.index.log seq 3: indexid changed: 1533501509 -> 1464071305 (sync_offset=168)
Aug 06 23:19:24 lda(user05): Error: Transaction log file /mnt/mail//user05/Maildir/.Queue.A_Sup.group_05/dovecot.index.log: marked corrupted
Aug 06 23:19:24 lda: Debug: Loading modules from directory: /usr/lib64/dovecot
Aug 06 23:19:24 lda(user05): Error: Corrupted index file /mnt/mail//user05/Maildir/.Queue.A_Sup.group_05/dovecot.index: messages_count too large (2915 > 85)
Aug 06 23:19:24 lda(user05): Warning: fscking index file /mnt/mail//user05/Maildir/.Queue.A_Sup.group_05/dovecot.index
Aug 06 23:19:24 lda(user05): Error: Corrupted index file /mnt/mail//user05/Maildir/.Queue.A_Sup.group_05/dovecot.index: messages_count too large (2915 > 85)
Aug 06 23:19:24 lda(user05): Warning: fscking index file /mnt/mail//user05/Maildir/.Queue.A_Sup.group_05/dovecot.index
Aug 06 23:19:24 lda(user05): Error: Fixed index file /mnt/mail//user05/Maildir/.Queue.A_Sup.group_05/dovecot.index: log_file_seq 670 -> 2
Aug 06 23:19:24 lda(user05): Error: Fixed index file /mnt/mail//user05/Maildir/.Queue.A_Sup.group_05/dovecot.index: messages_count 2915 -> 85
Aug 06 23:19:24 lda(user05): Panic: file mail-index-sync-update.c: line 1013 (mail_index_sync_map): assertion failed: (map->hdr.indexid == index->indexid || map->hdr.indexid == 0)
Aug 06 23:19:24 lda(user05): Error: Raw backtrace: /usr/lib64/dovecot/libdovecot.so.0(+0x6a06e) [0x7f1ada8a106e] -> /usr/lib64/dovecot/libdovecot.so.0(default_fatal_handler+0x2a) [0x7f1ada8a10da] -> /usr/lib64/dovecot/libdovecot.so.0(i_fatal+0) [0x7f1ada85952c] -> /usr/lib64/dovecot/libdovecot-storage.so.0(mail_index_sync_map+0x651) [0x7f1adabda2c1] -> /usr/lib64/dovecot/libdovecot-storage.so.0(mail_index_map+0x3e7) [0x7f1adabcab77] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0xb937d) [0x7f1adabc637d] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0xb9990) [0x7f1adabc6990] -> /usr/lib64/dovecot/libdovecot-storage.so.0(mail_index_open+0x8c) [0x7f1adabc6a7c] -> /usr/lib64/dovecot/libdovecot-storage.so.0(index_storage_mailbox_open+0x87) [0x7f1adabb79c7] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x4d882) [0x7f1adab5a882] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x4d963) [0x7f1adab5a963] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x802b4) [0x7f1adab8d2b4] -> /usr/lib64/dovecot/libdovecot-storage.so.0(mailbox_open+0x20) [0x7f1adab8d430] -> /usr/lib64/dovecot/libdovecot-lda.so.0(mail_deliver_save_open+0xad) [0x7f1adae3240d] -> /usr/lib64/dovecot/libdovecot-sieve.so.0(+0x3f0a2) [0x7f1ad9e130a2] -> /usr/lib64/dovecot/libdovecot-sieve.so.0(sieve_result_execute+0xc5) [0x7f1ad9e0b0f5] -> /usr/lib64/dovecot/libdovecot-sieve.so.0(sieve_multiscript_run+0x119) [0x7f1ad9e1b3c9] -> /usr/lib64/dovecot/lib90_sieve_plugin.so(+0x2e97) [0x7f1ada062e97] -> /usr/lib64/dovecot/libdovecot-lda.so.0(mail_deliver+0x4a) [0x7f1adae32b3a] -> /usr/libexec/dovecot/deliver(main+0x3b5) [0x556390a1e885] -> /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f1ada48c445] -> /usr/libexec/dovecot/deliver(+0x318c) [0x556390a1f18c]


dovecot -n   output:

===========
# 2.2.10: /etc/dovecot/dovecot.conf
# OS: Linux 3.10.0-862.3.2.el7.x86_64 x86_64 CentOS Linux release 7.5.1804 (Core)  fuse.encfs
auth_verbose = yes
first_valid_uid = 1000
lda_mailbox_autocreate = yes
log_path = /var/log/dovecot.log
mail_debug = yes
mail_home = /mnt/mail/%d/%n
mail_location = maildir:/mnt/mail/%d/%n/Maildir:INBOX=/mnt/mail/%d/%n/Maildir
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox dat
e ihave
mbox_write_locks = fcntl
namespace inbox {
  inbox = yes
  location =
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix =
}
passdb {
  driver = pam
}
plugin {
  setting_name = value sieve
  sieve = /mnt/mail/%d/%n/.dovecot.sieve
  sieve_after = /etc/dovecot/sieve/after/
  sieve_before = /etc/dovecot/sieve/before/
  sieve_dir = /mnt/mail/%d/%n/sieve
}
protocols = imap pop3 lmtp sieve
service imap-login {
  process_limit = 2000
}
service managesieve-login {
  inet_listener sieve {
    port = 4190
  }
  process_min_avail = 0
  service_count = 1
  vsz_limit = 64 M
}
service managesieve {
  process_limit = 1024
}
ssl = required
ssl_ca = </etc/CERT/SSL_CA_Bundle.pem
ssl_cert = </etc/CERT/po.com.crt
ssl_key = </etc/CERT/po.com.key
ssl_protocols = !SSLv2 !SSLv3
userdb {
  driver = passwd
}
protocol lda {
  mail_plugins = " sieve"
}
protocol imap {
  mail_max_userip_connections = 20
}
================