Keydb-rdb-bgsave never competes

Hello! We are running keydb 6.2.1 on Debian/Buster and the regular RDB bgsave processes keep running and never complete. Once the process gets killed, Keydb spawns another processes which immediately completes.

Can anyone help us to debug the issue?

# lsof -n -p 13536 |grep aof
COMMAND     PID  USER   FD      TYPE             DEVICE   SIZE/OFF     NODE NAME
keydb-ser 13536 keydb   38w      REG              254,1 1141467983   395961 /var/lib/keydb/appendonly.aof

# lsof -n -p 13536 |grep aof
COMMAND     PID  USER   FD      TYPE             DEVICE   SIZE/OFF     NODE NAME
keydb-ser 13536 keydb   38w      REG              254,1 1144103560   395961 /var/lib/keydb/appendonly.aof  

# lsof -n -p 13536 |grep aof ; ls -l /var/lib/keydb/appendonly.aof
keydb-ser 13536 keydb   38w      REG              254,1 1158861410   395961 /var/lib/keydb/appendonly.aof
-rw-rw---- 1 keydb keydb 1158861410 Nov 26 15:42 /var/lib/keydb/appendonly.aof

Config:

egrep -v '^#|^$' /etc/keydb/keydb.conf
protected-mode yes
port 6379
tcp-backlog 511
timeout 0
tcp-keepalive 300
daemonize yes
supervised systemd
pidfile /var/run/keydb/keydb-server.pid
loglevel notice
logfile ""
syslog-enabled yes
syslog-ident keydb
syslog-facility local0
databases 32
always-show-logo no
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename dump.rdb
dir /var/lib/keydb/
replicaof 10.0.0.10 6379
replica-serve-stale-data yes
replica-read-only yes
repl-diskless-sync no
repl-diskless-sync-delay 5
repl-disable-tcp-nodelay no
repl-backlog-size 1gb
replica-priority 100
aclfile /etc/keydb/users.acl
maxmemory 20gb
maxmemory-policy noeviction
lazyfree-lazy-eviction no
lazyfree-lazy-expire no
lazyfree-lazy-server-del no
replica-lazy-flush no
appendonly yes
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
aof-load-truncated yes
aof-use-rdb-preamble yes
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
latency-monitor-threshold 0
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-size -2
list-compress-depth 0
set-max-intset-entries 512
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
hll-sparse-max-bytes 3000
stream-node-max-bytes 4096
stream-node-max-entries 100
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit replica 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
dynamic-hz yes
aof-rewrite-incremental-fsync yes
rdb-save-incremental-fsync yes
server-threads 4
active-replica yes