error File exists

[kovaga]

/usr/local/bin/buttersink -d / ssh://[email protected]/mnt/backup_fs/asusjka Warning: Permanently added the ECDSA host key for IP address '192.168.xxx.15' to the list of known hosts.
S|Duplicate effective uuid d908d7ea-5117-ce44-bc18-a33081253c56 in 'snapshot' and '/asusjka/.snapshots/639/snapshot'
S|Duplicate effective uuid d5fc027d-27fc-7645-94df-fd636af7ab35 in '/mnt/backup_fs/xpska/snapshot' and '/xpska/home/.snapshots/4330/snapshot'
Remote version: {u'btrfs': u'btrfs-progs v5.4.1', u'buttersink': u'0.6.9-9-g5cc37e3', u'linux': u'Linux-5.3.0-40-generic-x86_64-with-Ubuntu-18.04-bionic'}
measured size (0 bytes), estimated size (0 bytes)
Optimal synchronization:
222.1 GiB from 31 diffs in ssh://[email protected]/mnt/backup_fs/asusjka
222.1 GiB from 31 diffs in TOTAL
Keep: d95c...fdae /mnt/backup_fs/asusjka/home/.snapshots/605/snapshot from None (47.9 GiB)
Keep: 4701...540a /mnt/backup_fs/asusjka/.snapshots/627/snapshot from None (15.3 GiB)
Keep: e949...a766 /mnt/backup_fs/asusjka/.snapshots/640/snapshot from None (13.34 GiB)
Keep: d908...3c56 /mnt/backup_fs/asusjka/.snapshots/639/snapshot from None (13.33 GiB)
Keep: 2b64...6d1d /mnt/backup_fs/asusjka/.snapshots/638/snapshot from None (13.32 GiB)
Keep: 60f7...7c91 /mnt/backup_fs/asusjka/.snapshots/623/snapshot from None (16.5 GiB)
Keep: 236c...d82d /mnt/backup_fs/asusjka/.snapshots/449/snapshot from None (11.15 GiB)
Keep: 8b79...8e7d /mnt/backup_fs/asusjka/.snapshots/625/snapshot from None (16.48 GiB)
Keep: 611b...e381 /mnt/backup_fs/asusjka/home/.snapshots/606/snapshot from None (47.9 GiB)
Keep: b13a...bab3 /mnt/backup_fs/asusjka/.snapshots/636/snapshot from e949...a766 /mnt/backup_fs/asusjka/.snapshots/640/snapshot (~2.59 GiB)
S|Copy e949...a766 to /mnt/backup_fs/asusjka/snapshot
ERROR: {u'traceback': u'File "build/bdist.linux-x86_64/egg/buttersink/ioctl.py", line 318, in call', u'errorType': u'IOError', u'command': u'keep', u'server': True, u'error': u"[Errno 17] File exists: u'/mnt/backup_fs/asusjka'"}.

I have recently moved the btrfs backups to a different server, and now I get the File exists error.
Frst time the sync goes fine, while the second time it throws a "File exists" error.

What could be the problem?

[AmesCornish]

What happens if you put a '/' on the end of the destination path?

[kovaga]

Same thing haappens.

/usr/local/bin/buttersink -d / ssh://[email protected]/mnt/backup_fs/asusjka/
S|Duplicate effective uuid d908d7ea-5117-ce44-bc18-a33081253c56 in 'snapshot' and '/asusjka/.snapshots/639/snapshot'
S|Duplicate effective uuid d5fc027d-27fc-7645-94df-fd636af7ab35 in '/mnt/backup_fs/xpska/snapshot' and '/xpska/home/.snapshots/4330/snapshot'
Remote version: {u'btrfs': u'btrfs-progs v5.4.1', u'buttersink': u'0.6.9-9-g5cc37e3', u'linux': u'Linux-5.3.0-40-generic-x86_64-with-Ubuntu-18.04-bionic'}
Measuring 9406...0866 //.snapshots/644/snapshot from 79f9...19c6 //.snapshots/642/snapshot (~12.99 MiB)
0:00:04.820633: Sent 203.5 MiB ETA: None (354 Mbps )

Measuring 3d2f...52c6 //.snapshots/641/snapshot from 79f9...19c6 //.snapshots/642/snapshot (~8.977 MiB)
0:00:00.496591: Sent 21.19 MiB ETA: None (358 Mbps )

{SNIP}
200.2 GiB from 24 diffs in ssh://[email protected]/mnt/backup_fs/asusjka
201 GiB from 31 diffs in TOTAL
Keep: d95c...fdae /mnt/backup_fs/asusjka/home/.snapshots/605/snapshot from None (47.9 GiB)
Keep: 79f9...19c6 /mnt/backup_fs/asusjka/.snapshots/642/snapshot from None (13.38 GiB)
Keep: 4701...540a /mnt/backup_fs/asusjka/.snapshots/627/snapshot from None (15.3 GiB)
Keep: e949...a766 /mnt/backup_fs/asusjka/.snapshots/640/snapshot from None (13.34 GiB)
Keep: d908...3c56 /mnt/backup_fs/asusjka/.snapshots/639/snapshot from None (13.33 GiB)
Keep: 236c...d82d /mnt/backup_fs/asusjka/.snapshots/449/snapshot from None (11.15 GiB)
Keep: 8b79...8e7d /mnt/backup_fs/asusjka/.snapshots/625/snapshot from None (16.48 GiB)
Keep: 611b...e381 /mnt/backup_fs/asusjka/home/.snapshots/606/snapshot from None (47.9 GiB)
Xfer: 9406...0866 //.snapshots/644/snapshot from 79f9...19c6 //.snapshots/642/snapshot (203.5 MiB)
0:00:20.318449: Sent 203.5 MiB of 203.5 MiB (100%) ETA: 0:00:00 (84 Mbps )
Keep: 0d0a...13c8 /mnt/backup_fs/asusjka/.snapshots/620/snapshot from e949...a766 /mnt/backup_fs/asusjka/.snapshots/640/snapshot (~3.276 GiB)
S|Copy e949...a766 to /mnt/backup_fs/asusjka/snapshot
ERROR: {u'traceback': u'File "build/bdist.linux-x86_64/egg/buttersink/ioctl.py", line 318, in call', u'errorType': u'IOError', u'command': u'keep', u'server': True, u'error': u"[Errno 17] File exists: u'/mnt/backup_fs/asusjka'"}.