PBS Backup failes Suspended but works in SNAPSHOT mode

[lemonbiter]

Hi there,
I am having an issue running a backup Job. If I run the job (of an LXC that runs ioBroker) as SUSPENDED, I get an error message as follows:

INFO: starting new backup job: vzdump 200 --node pve --all 0 --mode suspend --storage PBS-DINAX --prune-backups 'keep-last=5' --notes-template '{{guestname}}' --mailnotification failure
INFO: Starting Backup of VM 200 (lxc)
INFO: Backup started at 2024-01-02 01:03:36
INFO: status = running
INFO: backup mode: suspend
INFO: ionice priority: 7
INFO: CT Name: ioBroker
INFO: including mount point rootfs ('/') in backup
INFO: starting first sync /proc/1131/root/ to /var/tmp/vzdumptmp1596740_200
ERROR: Backup of VM 200 failed - command 'rsync --stats -h -X -A --numeric-ids -aH --delete --no-whole-file --sparse --one-file-system --relative '--exclude=/tmp/?*' '--exclude=/var/tmp/?*' '--exclude=/var/run/?*.pid' /proc/1131/root//./ /var/tmp/vzdumptmp1596740_200' failed: exit code 11
INFO: Failed at 2024-01-02 01:04:33
INFO: Backup job finished with errors
INFO: notified via target `mail-to-root`
TASK ERROR: job errors

Running the backup of the very same LXC, but as SNAPSHOT, all works like a charme. Here is the Task

INFO: starting new backup job: vzdump 200 --all 0 --mode snapshot --node pve --storage PBS-DINAX --mailnotification failure --prune-backups 'keep-last=5' --notes-template '{{guestname}}'
INFO: Starting Backup of VM 200 (lxc)
INFO: Backup started at 2024-01-02 00:53:00
INFO: status = running
INFO: CT Name: ioBroker
INFO: including mount point rootfs ('/') in backup
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: create storage snapshot 'vzdump'
  Logical volume "snap_vm-200-disk-0_vzdump" created.
INFO: creating Proxmox Backup Server archive 'ct/200/2024-01-01T23:53:00Z'
INFO: run: /usr/bin/proxmox-backup-client backup --crypt-mode=none pct.conf:/var/tmp/vzdumptmp1590780_200/etc/vzdump/pct.conf root.pxar:/mnt/vzsnap0 --include-dev /mnt/vzsnap0/./ --skip-lost-and-found --exclude=/tmp/?* --exclude=/var/tmp/?* --exclude=/var/run/?*.pid --backup-type ct --backup-id 200 --backup-time 1704153180 --repository root@pam@10.0.1.7:ProxmoxBackupQNAPDINAX
INFO: Starting backup: ct/200/2024-01-01T23:53:00Z
INFO: Client name: pve
INFO: Starting backup protocol: Tue Jan  2 00:53:01 2024
INFO: Downloading previous manifest (Mon Jan  1 14:26:27 2024)
INFO: Upload config file '/var/tmp/vzdumptmp1590780_200/etc/vzdump/pct.conf' to 'root@pam@10.0.1.7:8007:ProxmoxBackupQNAPDINAX' as pct.conf.blob
INFO: Upload directory '/mnt/vzsnap0' to 'root@pam@10.0.1.7:8007:ProxmoxBackupQNAPDINAX' as root.pxar.didx
INFO: root.pxar: had to backup 219.849 MiB of 38.634 GiB (compressed 79.343 MiB) in 64.06s
INFO: root.pxar: average backup speed: 3.432 MiB/s
INFO: root.pxar: backup was done incrementally, reused 38.419 GiB (99.4%)
INFO: Uploaded backup catalog (2.724 MiB)
INFO: Duration: 106.77s
INFO: End Time: Tue Jan  2 00:54:47 2024
INFO: adding notes to backup
INFO: prune older backups with retention: keep-last=5
INFO: running 'proxmox-backup-client prune' for 'ct/200'
INFO: pruned 0 backup(s)
INFO: cleanup temporary 'vzdump' snapshot
  Logical volume "snap_vm-200-disk-0_vzdump" successfully removed.
INFO: Finished Backup of VM 200 (00:01:50)
INFO: Backup finished at 2024-01-02 00:54:50
INFO: Backup job finished successfully
INFO: notified via target `mail-to-root`
TASK OK

I am a very beginner and without any linux knowledge. Since I was having an issue with the PBS week before (I could get no job backuped of no LXC and no VM) I have the slight feeling, that there might be an older "unsuccesful" backup job of the same LXC "stuck" somewhere hidden on the PBS...
But that might be a dumb idea...

Please help
Thank
LEM