Backup error: PRocess already running with pid 'ID'

[lenaulrich]

Version: 0.2.8
Expected behaviour: Backup is created successfully
Actual behaviour: For two VMs the backup fails every other day.
Error message: ACTION: Backup
Start backup 2021-04-19 17:00:01
ERROR: Process already running with pid 192715
expr: syntax error: unexpected argument ‘1618844401’ /usr/sbin/eve4pve-barc: line 1507: local: 0/0: division by 0 (error token is "0")

When running ps ax | grep 192715 there is no process with the stated pid running.

Cron:
0 17 * * * root eve4pve-barc backup --vmid=149245 --label='daily' --path='/mnt/pve/blurred/barc' --keep=9
0 0 * * 0 root eve4pve-barc backup --vmid=149245 --label='weekly' --path='/mnt/pve/blurred/barc' --keep=3
0 17 * * * root eve4pve-barc backup --vmid=149206 --label='daily' --path='/mnt/pve/blurred/barc' --keep=9
0 0 * * 0 root eve4pve-barc backup --vmid=149206 --label='weekly' --path='/mnt/pve/blurred/barc' --keep=3

We tried creating a fresh backup, this didn't help. To achieve this we moved the old backup to a new folder so the backup folder is empty again.

Any advise?