pfSense

I have a OpenVPN server running on interface WAN2 which has a single OpenVPN client connecting to it.
The OpenVPN server crashes with error "pid 52477 (openvpn), jid 0, uid 0: exited on signal 8 (core dumped)"
when the client closes the OpenVPN connection.
The closing of the vpn client is done with this command:

pkill -SIGTERM -f 'openvpn gateway-udp-XYZ.ovpn'

The same configuration worked without issue on PfSense 2.6.0

Version of the OpenVPN client is:

OpenVPN 2.3.4 arm-unknown-linux-gnueabihf [SSL (OpenSSL)] [LZO] [EPOLL] [PKCS11] [MH] [IPv6] built on Jun 27 2017
library versions: OpenSSL 1.0.1t 3 May 2016, LZO 2.08
Originally developed by James Yonan
Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
Compile time defines: enable_crypto=yes enable_debug=yes enable_def_auth=yes enable_dependency_tracking=no enable_dlopen=unknown enable_dlopen_self=unknown enable_dlopen_self_static=unknown enable_fast_install=yes enable_fragment=yes enable_http_proxy=yes enable_iproute2=yes enable_libtool_lock=yes enable_lzo=yes enable_lzo_stub=no enable_maintainer_mode=no enable_management=yes enable_multi=yes enable_multihome=yes enable_pam_dlopen=no enable_password_save=yes enable_pedantic=no enable_pf=yes enable_pkcs11=yes enable_plugin_auth_pam=yes enable_plugin_down_root=yes enable_plugins=yes enable_port_share=yes enable_selinux=no enable_server=yes enable_shared=yes enable_shared_with_static_runtimes=no enable_small=no enable_socks=yes enable_ssl=yes enable_static=yes enable_strict=no enable_strict_options=no enable_systemd=yes enable_win32_dll=yes enable_x509_alt_username=yes with_crypto_library=openssl with_gnu_ld=yes with_ifconfig_path=/sbin/ifconfig with_iproute_path=/sbin/ip with_mem_check=no with_plugindir='${prefix}/lib/openvpn' with_route_path=/sbin/route with_sysroot=no

Client OpenVPN config:

dev tun
persist-tun
persist-key
cipher AES-256-CBC
auth SHA512
tls-client
client
resolv-retry infinite
remote xyz.demo.de 6789 udp
verify-x509-name "OpenVPN_Server_XYZ" name
pkcs12 gateway-udp-XYZ.p12
tls-auth gateway-udp-XYZ-tls.key 1
ns-cert-type server
fragment 1300
mssfix
persist-tun
persist-key
tls-version-min 1.2

tls-cipher TLS-ECDHE-RSA-WITH-AES-128-GCM-SHA256:TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256:TLS-ECDHE-RSA-WITH-AES-256-GCM-SHA384:TLS-DHE-RSA-WITH-AES-256-CBC-SHA256

daemon
keepalive 30 240

OpenVPN server config:

dev ovpns2
verb 1
dev-type tun
dev-node /dev/tun2
writepid /var/run/openvpn_server2.pid
#user nobody
#group nobody
script-security 3
daemon
keepalive 10 60
ping-timer-rem
persist-tun
persist-key
proto udp4
auth SHA512
up /usr/local/sbin/ovpn-linkup
down /usr/local/sbin/ovpn-linkdown
client-connect /usr/local/sbin/openvpn.attributes.sh
client-disconnect /usr/local/sbin/openvpn.attributes.sh
learn-address "/usr/local/sbin/openvpn.learn-address.sh xyz.local.lan"
local 192.168.179.2
tls-server
server 192.168.194.0 255.255.255.248
client-config-dir /var/etc/openvpn/server2/csc
tls-verify "/usr/local/sbin/ovpn_auth_verify tls 'OpenVPN_Server_XYZ' 1"
lport 6789
management /var/etc/openvpn/server2/sock unix
push "route 192.168.124.0 255.255.255.0"
push "route 192.168.76.0 255.255.255.0"
push "route 192.168.100.0 255.255.255.0"
push "dhcp-option DOMAIN xyz.local.lan"
remote-cert-tls client
capath /var/etc/openvpn/server2/ca
cert /var/etc/openvpn/server2/cert
key /var/etc/openvpn/server2/key
dh /etc/dh-parameters.2048
tls-auth /var/etc/openvpn/server2/tls-auth 0
data-ciphers AES-256-GCM:AES-128-GCM:AES-256-CBC
data-ciphers-fallback AES-256-CBC
allow-compression asym
persist-remote-ip
float
topology subnet
fragment 1300
mssfix
persist-tun
persist-key
tls-version-min 1.2
keepalive 30 240

tls-cipher TLS-ECDHE-RSA-WITH-AES-128-GCM-SHA256:TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256:TLS-ECDHE-RSA-WITH-AES-256-GCM-SHA384:TLS-DHE-RSA-WITH-AES-256-CBC-SHA256