Snapd or LXD snap keeps storage device "in use" even when it is unmounted

Hi all, could you please tell me if there is any way how to enforce snapd (or possibly just LXD snap) to “release” all devices? The thing is I want to use Ubuntu 22.04 in Azure with ephemeral disk which is (unfortunately) by default formatted and mounted to /mnt via /etc/fstab. To repartition it I unmount it first which is successful, no errors reported and mountpoint is empty. However, when I try to create new partition table fdisk/parted warns me, that the device is still in use and that updated partition table will not be visible inside kernel until reboot.

I was surprised as the device should not be mounted and I tried to find the reason. And it seems that this is most probably caused by snapd or fact that LXD container is installed by default. All the configs are default without changes and no snap was executed (the machine is just freshly booted from official image). Because when I remove LXD container (snap remove lxd), the device is immediately released and I can partition it without any issues. Unfortunately, my knowledge of snaps is very limited and I do not know why and could not find any magical command which can do the same thing without uninstalling the snap. Stopping the snapd service and socket did not help.

OS: Ubuntu 22.04.1 LTS snap(d) version: 2.57.6 LXD snap version: 5.0.1-9dcf35b

Thank you for your help!