No permission to destroy snapshot on USERDATA

For years I destroyed my snapshots as indicated, but in this specific case it does NOT work anymore. See copy of command:

bertadmin@Host-R3:~$ zsysctl show
Name: rpool/ROOT/ubuntu_57vi20
ZSys: true
Last Used: current
History:
  - Name: rpool/ROOT/ubuntu_57vi20@211111-linux13-21
    Created on: 2021-11-11 22:43:53
  - Name: rpool/ROOT/ubuntu_57vi20@211019-proposed13-20
    Created on: 2021-10-19 13:52:04
Users:
  - Name: bertadmin
    History:
     - rpool/USERDATA/bertadmin_vz8u5n@211111-linux13-21 (2021-11-11 22:43:53)
     - rpool/USERDATA/bertadmin_vz8u5n@211019-proposed13-20 (2021-10-19 13:52:04)
     - rpool/USERDATA/bertadmin_vz8u5n@211015-proposed13-19 (2021-10-15 19:06:21)
  - Name: root
    History:
     - rpool/USERDATA/root_vz8u5n@211111-linux13-21 (2021-11-11 22:43:53)
     - rpool/USERDATA/root_vz8u5n@211019-proposed13-20 (2021-10-19 13:52:04)
bertadmin@Host-R3:~$ sudo zfs destroy rpool/USERDATA/bertadmin_vz8u5n@211015-proposed13-19
cannot destroy snapshot rpool/USERDATA/bertadmin_vz8u5n@211015-proposed13-19: dataset is busy

The snapshots are taken with "zsysctl save".
Note that I can destroy the autozsys snapshots without issues in this way.
Note that even after the reboot using the recovery entry with the root directory, I can't delete the snapshot and I tried the same with another system booting for an ext4 disk.

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: udisks2 2.9.4-1
ProcVersionSignature: Ubuntu 5.13.0-21.21-generic 5.13.18
Uname: Linux 5.13.0-21-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu71
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
CustomUdevRuleFiles: hide-partitions.rules 70-snap.firefox.rules 70-snap.snapd.rules 70-snap.snap-store.rules 60-vboxdrv.rules
Date: Fri Nov 12 07:01:41 2021
InstallationDate: Installed on 2021-10-09 (33 days ago)
InstallationMedia: Ubuntu 21.04 "Hirsute Hippo" - Release amd64 (20210420)
MachineType: To Be Filled By O.E.M. To Be Filled By O.E.M.
ProcKernelCmdLine: BOOT_IMAGE=/BOOT/ubuntu_57vi20@/vmlinuz-5.13.0-21-generic root=ZFS=rpool/ROOT/ubuntu_57vi20 ro quiet splash vt.handoff=1
SourcePackage: udisks2
Symptom: storage
Title: No permission to access files on storage device
UpgradeStatus: Upgraded to impish on 2021-10-14 (28 days ago)
dmi.bios.date: 03/12/2021
dmi.bios.release: 5.17
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P4.50
dmi.board.name: B450M-HDV R4.0
dmi.board.vendor: ASRock
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP4.50:bd03/12/2021:br5.17:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnB450M-HDVR4.0:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:skuToBeFilledByO.E.M.:
dmi.product.family: To Be Filled By O.E.M.
dmi.product.name: To Be Filled By O.E.M.
dmi.product.sku: To Be Filled By O.E.M.
dmi.product.version: To Be Filled By O.E.M.
dmi.sys.vendor: To Be Filled By O.E.M.