dagent crashed after receiving email

Hello,

our kopano dagent is crashing from time to time if it gets a mail delivered from postfix.
I have taken a look at the log files. And as I could see in postfix logs the crash happened, when postfix is trying to deliver mails originating from our confluence server.

Excerpt from kopano dagent.log

Mon May 18 11:30:03 2020: [crit   ] Fatal error detected. Please report all following information.
Mon May 18 11:30:03 2020: [crit   ] kopano-dagent 8.7.9.0
Mon May 18 11:30:03 2020: [crit   ] OS: SUSE Linux Enterprise Server 12 SP4 (Linux 4.12.14-95.48-default x86_64)
Mon May 18 11:30:03 2020: [crit   ] Thread name: kopano-dagent
Mon May 18 11:30:03 2020: [crit   ] Peak RSS: 33196
Mon May 18 11:30:03 2020: [crit   ] Pid 10864 caught SIGSEGV (11), traceback:
Mon May 18 11:30:03 2020: [crit   ] Backtrace:
Mon May 18 11:30:03 2020: [crit   ] f0. /usr/lib64/libkcutil.so.0(+0x4bf1b) [0x7f8875f65f1b]
Mon May 18 11:30:03 2020: [crit   ] f1. /usr/lib64/libkcutil.so.0(+0x32d7f) [0x7f8875f4cd7f]
Mon May 18 11:30:03 2020: [crit   ] f2. /usr/lib64/libkcutil.so.0(+0x34956) [0x7f8875f4e956]
Mon May 18 11:30:03 2020: [crit   ] f3. /lib64/libpthread.so.0(+0x10c70) [0x7f887589bc70]
Mon May 18 11:30:03 2020: [crit   ] f4. /usr/lib64/libpython2.7.so.1.0(+0xcb454) [0x7f886d211454]
Mon May 18 11:30:03 2020: [crit   ] f5. /usr/lib64/libpython2.7.so.1.0(PyType_Ready+0x7c2) [0x7f886d213012]
Mon May 18 11:30:03 2020: [crit   ] f6. /usr/lib64/libkcpyplug.so.0(+0x28a2) [0x7f8864e278a2]
Mon May 18 11:30:03 2020: [crit   ] f7. /usr/lib64/libkcpyplug.so.0(+0x2905) [0x7f8864e27905]
Mon May 18 11:30:03 2020: [crit   ] f8. /usr/lib64/libkcpyplug.so.0(+0x2958) [0x7f8864e27958]
Mon May 18 11:30:03 2020: [crit   ] f9. /usr/lib64/libkcpyplug.so.0(+0x3075) [0x7f8864e28075]
Mon May 18 11:30:03 2020: [crit   ] f10. /usr/lib64/libkcpyplug.so.0(+0x39cc) [0x7f8864e289cc]
Mon May 18 11:30:03 2020: [crit   ] f11. /usr/sbin/kopano-dagent() [0x414d87]
Mon May 18 11:30:03 2020: [crit   ] f12. /usr/sbin/kopano-dagent() [0x419d56]
Mon May 18 11:30:03 2020: [crit   ] f13. /usr/lib64/libkcutil.so.0(_ZN2KC18unix_fork_functionEPFPvS0_ES0_iPi+0x6e) [0x7f8875f6391e]
Mon May 18 11:30:03 2020: [crit   ] f14. /usr/sbin/kopano-dagent() [0x417332]
Mon May 18 11:30:03 2020: [crit   ] f15. /usr/sbin/kopano-dagent() [0x40b22c]
Mon May 18 11:30:03 2020: [crit   ] f16. /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f887498b765]
Mon May 18 11:30:03 2020: [crit   ] f17. /usr/sbin/kopano-dagent() [0x40cc89]
Mon May 18 11:30:03 2020: [crit   ] Signal errno: Success, signal code: 1
Mon May 18 11:30:03 2020: [crit   ] Sender pid: 1836426880, sender uid: 32648, si_status: 0
Mon May 18 11:30:03 2020: [crit   ] Signal value: 0, faulting address: 0x7f886d75a680

And here is the message from postfix/lmtp

2020-05-18T11:30:02.379354+02:00 mail postfix/lmtp[10800]: 1395011BD521: to=<XXXXXXXX@XXXXXXXXXX.XXX>, relay=127.0.0.1[127.0.0.1]:2003, conn_use=2, delay=0.21, delays=0.13/0/0/0.08, dsn=4.4.2, status=deferred (lost connection with 127.0.0.1[127.0.0.1] while sending end of data -- message may be sent more than once)

What is the cause of the crash?

Regards
Ulrich