Timeshift shows Size and Unshared '0 B' when first start after boot.

[catscarlet]

Describe the bug
Timeshift shows Size and Unshared 'Zero' when first-time start after boot.

To Reproduce

1. Boot/Reboot the computer.
2. Start Timeshift.
3. Get the result.

Expected behavior
Timeshift shows values correctly.

Screenshots

System:

• linuxmint-20.2-cinnamon-64bit, kernel 5.4.0-90
• cinnamon 5.0.7
• Timeshift v20.11.1
• Use btrfs for / but also have some other EXT4 partitions mounted. (I also do this in the same way on my other laptop without this issue)

More:
After this. Close Timeshit, and reopen it again, and Timeshift starts to show the correct value.

Log:

Click to expand!

[10:54:28] Session log file: /var/log/timeshift/2021-11-23_10-54-28_gui.log
[10:54:28] Distribution: LinuxMint 20.2 (uma)
[10:54:28] DIST_ID: LinuxMint
[10:54:28] Main: check_dependencies()
[10:54:28] Main: add_default_exclude_entries()
[10:54:28] Main: add_default_exclude_entries(): exit
[10:54:28] update_partitions()
[10:54:28] Device: get_disk_space_using_df(): 4
[10:54:28] Device: get_mounted_filesystems_using_mtab(): 4
[10:54:28] Device: get_filesystems(): 22
[10:54:28] partition list updated
[10:54:28] detect_system_devices()
[10:54:28] /boot/efi is mapped to device: /dev/sda1, UUID=24B8-EEA9
[10:54:28] / is mapped to device: /dev/sda5, UUID=77a0615e-5877-4946-ae03-69e94e85b44a, subvol=@
[10:54:28] /home is mapped to device: /dev/sda6, UUID=4b7792d3-b8d7-4a14-a9c7-ec95f0dac0e6
[10:54:28] Searching subvolume for system at path: /
[10:54:28] Found subvolume: @, on device: /dev/sda5
[10:54:28] Users: root cat
[10:54:28] Encrypted home users: 
[10:54:28] Encrypted home dirs:

[10:54:28] Encrypted private dirs:

[10:54:28] Main: load_app_config()
[10:54:28] App config loaded: /etc/timeshift/timeshift.json
[10:54:28] IconManager: init()
[10:54:28] bin_path: /usr/bin/timeshift-gtk
[10:54:28] found images directory: /usr/share/timeshift/images
[10:54:28] Main(): ok
[10:54:28] Main: initialize_repo()
[10:54:28] backup_uuid=77a0615e-5877-4946-ae03-69e94e85b44a
[10:54:28] backup_parent_uuid=
[10:54:28] Setting snapshot device from config file
[10:54:28] repo: creating from uuid
[10:54:28] SnapshotRepo: from_uuid(): BTRFS
[10:54:28] uuid=77a0615e-5877-4946-ae03-69e94e85b44a
[10:54:28] SnapshotRepo: init_from_device()
[10:54:28] 
[10:54:28] SnapshotRepo: unlock_and_mount_devices()
[10:54:28] device=/dev/sda5
[10:54:28] SnapshotRepo: unlock_and_mount_device()
[10:54:28] device=/dev/sda5
[10:54:28] Device: get_mounted_filesystems_using_mtab(): 4
[10:54:28] ------------------
[10:54:28] arg=77a0615e-5877-4946-ae03-69e94e85b44a, device=/dev/sda5
[10:54:28] /
[10:54:28] ------------------
[10:54:28] Device: get_mounted_filesystems_using_mtab(): 4
[10:54:28] Mounted '/dev/sda5' at '/run/timeshift/backup'
[10:54:28] Searching subvolume for system at path: /run/timeshift/backup/@
[10:54:28] Found subvolume: @, on device: /dev/sda5
[10:54:28] SnapshotRepo: load_snapshots()
[10:54:28] Querying subvolume info...
[10:54:28] query_subvolume_id():@
[10:54:28] btrfs subvolume list '/run/timeshift/backup'
[10:54:28] query_subvolume_quota():@
[10:54:28] btrfs qgroup show --raw '/run/timeshift/backup'
[10:54:28] btrfs qgroup show '/run/timeshift/backup'
[10:54:28] E: ERROR: can't list qgroups: quotas not enabled

[10:54:28] E: btrfs returned an error: 256
[10:54:28] E: Failed to query subvolume quota
[10:54:28] enable_subvolume_quota():@
[10:54:28] btrfs quota enable '/run/timeshift/backup'
[10:54:28] Enabled subvolume quota support
[10:54:28] query_subvolume_quota():@
[10:54:28] btrfs qgroup show  '/run/timeshift/backup'
[10:54:28] Query completed
[10:54:28] loading snapshots from '/run/timeshift/backup/timeshift-btrfs/snapshots': 5 found
[10:54:28] SnapshotRepo: unlock_and_mount_device(): exit
[10:54:28] Selected snapshot device: /dev/sda5
[10:54:28] Free space: 48.5 GB
[10:54:28] SnapshotRepo: check_status()
[10:54:28] SnapshotRepo: available()
[10:54:28] SnapshotRepo: has_btrfs_system()
[10:54:28] root_path=/run/timeshift/backup/@
[10:54:28] btrfs_mode=true
[10:54:28] is_available: ok
[10:54:28] SnapshotRepo: has_snapshots()
[10:54:28] SnapshotRepo: has_space()
[10:54:28] Device: get_disk_space_using_df(): 1
[10:54:28] Snapshot device: '/dev/sda5'
[10:54:28] Snapshot location: /run/timeshift/backup
[10:54:28] OK
[10:54:28] 5 snapshots, 48.5 GB free
[10:54:28] Status: HAS_SNAPSHOTS_HAS_SPACE
[10:54:28] 
[10:54:28] SnapshotRepo: check_status(): exit
[10:54:28] SnapshotRepo: init_from_device(): exit
[10:54:28] SnapshotRepo: from_uuid(): exit
[10:54:28] Main: initialize_repo(): exit
[10:54:28] MainWindow: MainWindow()
[10:54:28] SnapshotListBox: SnapshotListBox()
[10:54:28] SnapshotListBox: SnapshotListBox(): exit
[10:54:28] MainWindow: MainWindow(): exit
[10:54:28] MainWindow(): init_delayed()
[10:54:28] SnapshotRepo: available()
[10:54:28] SnapshotRepo: has_btrfs_system()
[10:54:28] root_path=/run/timeshift/backup/@
[10:54:28] btrfs_mode=true
[10:54:28] is_available: ok
[10:54:28] SnapshotRepo: available()
[10:54:28] SnapshotRepo: has_btrfs_system()
[10:54:28] root_path=/run/timeshift/backup/@
[10:54:28] btrfs_mode=true
[10:54:28] is_available: ok
[10:54:28] SnapshotRepo: load_snapshots()
[10:54:28] Querying subvolume info...
[10:54:28] query_subvolume_id():@
[10:54:28] btrfs subvolume list '/run/timeshift/backup'
[10:54:28] query_subvolume_quota():@
[10:54:28] btrfs qgroup show  '/run/timeshift/backup'
[10:54:28] Query completed
[10:54:28] loading snapshots from '/run/timeshift/backup/timeshift-btrfs/snapshots': 5 found
[10:54:28] SnapshotRepo: check_status()
[10:54:28] SnapshotRepo: available()
[10:54:28] SnapshotRepo: has_btrfs_system()
[10:54:28] root_path=/run/timeshift/backup/@
[10:54:28] btrfs_mode=true
[10:54:28] is_available: ok
[10:54:28] SnapshotRepo: has_snapshots()
[10:54:28] SnapshotRepo: has_space()
[10:54:28] Device: get_disk_space_using_df(): 1
[10:54:28] Snapshot device: '/dev/sda5'
[10:54:28] Snapshot location: /run/timeshift/backup
[10:54:28] OK
[10:54:28] 5 snapshots, 48.5 GB free
[10:54:28] Status: HAS_SNAPSHOTS_HAS_SPACE
[10:54:28] 
[10:54:28] SnapshotRepo: check_status(): exit
[10:54:28] SnapshotRepo: has_snapshots()
[10:54:28] SnapshotRepo: has_snapshots()
[10:54:28] MainWindow(): init_delayed(): exit