Tim, with reference to the ask.openstack query, the MultiPart object never received the delete, hence the container was not updated.

root@VM:~# s3cmd del --recursive --force --region us-east-1 s3://bucket9
delete: 's3://bucket9/2M_file.file'
delete: 's3://bucket9/firmimg.d7'
root@VM:~# s3cmd ls --region us-east-1 s3://bucket9
2019-01-03 08:21 105639142   s3://bucket9/firmimg.d7

Proxy-server logs:
root@VM:~# grep bucket9 /var/log/swift/proxy.log         
Jan  4 05:43:40.891106 hostname proxy-server: {'access_key': 'xxxxxxxxxxxxxxxxxxxxxxxf1717b67f', 'container_name': 'bucket9', '_timestamp': 1546580620.00000_0000000000000000, 'user_id': None, 'slo_enabled': True, '_signed_headers': set(['x-amz-content-sha256', 'host', 'x-amz-date']), 'string_to_sign': 'AWS4-HMAC-SHA256\n20190104T054340Z\n20190104/us-east-1/s3/aws4_request\n324616a0858b1da3e27453fa34401678f3c58e131dfbff23b99678bd493c3d0d', '_params_cache': {}, 'headers': <swift.common.swob.HeaderEnvironProxy object at 0x7f4e3fc97d50>, 'object_name': '', 'bucket_in_host': None, 'environ': {'HTTP_AUTHORIZATION': 'AWS xxxxxxxxxxxxxxxxxxxxxxxf1717b67f:c83ebdfe2e77e1a2c199611359e89a5309196b29c987ddd13dfe046f83339fa1', 'SCRIPT_NAME': '', 'keystone.token_auth': <keystonemiddleware.auth_token._user_plugin.UserAuthPlugin object at 0x7f4e3fb585d0>, 'webob.adhoc_attrs': {'response': <_AuthTokenResponse at 0x7f4e3fafcf50 200 OK>}, 'REQUEST_METHOD': 'GET', 'HTTP_X_AMZ_DATE': '20190104T054340Z', 'PATH_INFO': '/bucket9/', 'SERVER_PROTOCOL': 'HTTP/1.0', 'REMOTE_ADDR': '150.50.2.135', 'CONTENT_LENGTH': '0', 'eventlet.posthooks': [], 'RAW_PATH_INFO': '/bucket9/', 'REMOTE_PORT': '49285', 'eventlet.input': <eventlet.wsgi.Input object at 0x7f4e3fc53fd0>, 'HTTP_X_IDENTITY_STATUS': 'Invalid', 'wsgi.url_scheme': 'http', 'SERVER_PORT': '80', 'HTTP_X_AMZ_CONTENT_SHA256': 'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855', 'swift.leave_relative_location': True, 'wsgi.input': <eventlet.wsgi.Input object at 0x7f4e3fc53fd0>, 'HTTP_HOST': 'vsa-00000ae2-zadara-dev2.zadarazios.com', 'swift.cache': <swift.common.memcached.MemcacheRing object at 0x7f4e3fc6bf10>, 'wsgi.multithread': True, 'wsgi.version': (1, 0), 'SERVER_NAME': '150.50.2.135', 'GATEWAY_INTERFACE': 'CGI/1.1', 'wsgi.run_once': False, 'wsgi.errors': <swift.common.utils.LoggerFileObject object at 0x7f4e3fbf9fd0>, 'wsgi.multiprocess': False, 'swift.trans_id': 'tx79aefa29e485496fa408b-005c2ef28c', 'CONTENT_TYPE': None, 'swift3.auth_details': {'access_key': 'xxxxxxxxxxxxxxxxxxxxxxxf1717b67f', 'check_signature': <bound method SigV4Request.check_signature of <swift3.request.SigV4Request object at 0x7f4e3fc97090>>, 'string_to_sign': 'AWS4-HMAC-SHA256\n20190104T054340Z\n20190104/us-east-1/s3/aws4_request\n324616a0858b1da3e27453fa34401678f3c58e131dfbff23b99678bd493c3d0d', 'signature': 'c83ebdfe2e77e1a2c199611359e89a5309196b29c987ddd13dfe046f83339fa1'}, 'HTTP_ACCEPT_ENCODING': 'identity'}, 'token': None, 'signature': 'c83ebdfe2e77e1a2c199611359e89a5309196b29c987ddd13dfe046f83339fa1', 'account': None}
Jan  4 05:43:41.105368 hostname proxy-server: - - 04/Jan/2019/05/43/41 HEAD /v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9 HTTP/1.0 204 - Swift - - - - tx79aefa29e485496fa408b-005c2ef28c - 0.0432 TA - 1546580621.061520100 1546580621.104691029 0
Jan  4 05:43:41.169046 hostname proxy-server: 150.50.2.135 150.50.2.135 04/Jan/2019/05/43/41 GET /v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9%3Fformat%3Djson%26limit%3D1001 HTTP/1.0 200 - - gAAAAABcLvKM5Eb1... - 358 - tx79aefa29e485496fa408b-005c2ef28c - 0.1571 S3 - 1546580621.005058050 1546580621.162199974 0
Jan  4 05:43:41.216751 hostname proxy-server: {'access_key': 'xxxxxxxxxxxxxxxxxxxxxxxf1717b67f', 'container_name': 'bucket9', '_timestamp': 1546580621.00000_0000000000000000, 'user_id': None, 'slo_enabled': True, '_signed_headers': set(['x-amz-content-sha256', 'host', 'content-type', 'x-amz-date', 'content-md5']), 'string_to_sign': 'AWS4-HMAC-SHA256\n20190104T054341Z\n20190104/us-east-1/s3/aws4_request\n9633437c465d70100b14021a3d7387189b9141f3a47be756e6654745b0350039', '_params_cache': {'delete': ''}, 'headers': <swift.common.swob.HeaderEnvironProxy object at 0x7f4e3fbcb550>, 'object_name': '', 'bucket_in_host': None, 'environ': {'HTTP_AUTHORIZATION': 'AWS xxxxxxxxxxxxxxxxxxxxxxxf1717b67f:242660ea3ab0faad04f639c4f586f34dd48785d44e551919614a076d6ecf8af6', 'SCRIPT_NAME': '', 'keystone.token_auth': <keystonemiddleware.auth_token._user_plugin.UserAuthPlugin object at 0x7f4e3fc50f50>, 'webob.adhoc_attrs': {'response': <_AuthTokenResponse at 0x7f4e3fc50450 200 OK>}, 'REQUEST_METHOD': 'POST', 'HTTP_X_AMZ_DATE': '20190104T054341Z', 'PATH_INFO': '/bucket9/', 'SERVER_PROTOCOL': 'HTTP/1.0', 'QUERY_STRING': 'delete', 'REMOTE_ADDR': '150.50.2.135', 'CONTENT_LENGTH': '133', 'eventlet.posthooks': [], 'RAW_PATH_INFO': '/bucket9/', 'REMOTE_PORT': '49285', 'eventlet.input': <eventlet.wsgi.Input object at 0x7f4e3fc53210>, 'HTTP_X_IDENTITY_STATUS': 'Invalid', 'wsgi.url_scheme': 'http', 'HTTP_ETAG': 'a4c2265dec2b9c9c759012f32bbf808b', 'SERVER_PORT': '80', 'HTTP_X_AMZ_CONTENT_SHA256': 'fa37bbbd855040e36beb1f9024b7a79b296a7a565fc1df90e6b4fe432b311e3a', 'swift.leave_relative_location': True, 'wsgi.input': <eventlet.wsgi.Input object at 0x7f4e3fc53210>, 'HTTP_HOST': 'vsa-00000ae2-zadara-dev2.zadarazios.com', 'swift.cache': <swift.common.memcached.MemcacheRing object at 0x7f4e3fc6bf10>, 'wsgi.multithread': True, 'wsgi.version': (1, 0), 'SERVER_NAME': '150.50.2.135', 'GATEWAY_INTERFACE': 'CGI/1.1', 'wsgi.run_once': False, 'wsgi.errors': <swift.common.utils.LoggerFileObject object at 0x7f4e3fbf9fd0>, 'wsgi.multiprocess': False, 'swift.trans_id': 'tx78671d8454dd4a89a611a-005c2ef28d', 'HTTP_CONTENT_MD5': 'pMImXewrnJx1kBLzK7+Aiw==', 'CONTENT_TYPE': 'application/xml', 'swift3.auth_details': {'access_key': 'xxxxxxxxxxxxxxxxxxxxxxxf1717b67f', 'check_signature': <bound method SigV4Request.check_signature of <swift3.request.SigV4Request object at 0x7f4e3fbcb890>>, 'string_to_sign': 'AWS4-HMAC-SHA256\n20190104T054341Z\n20190104/us-east-1/s3/aws4_request\n9633437c465d70100b14021a3d7387189b9141f3a47be756e6654745b0350039', 'signature': '242660ea3ab0faad04f639c4f586f34dd48785d44e551919614a076d6ecf8af6'}, 'HTTP_ACCEPT_ENCODING': 'identity'}, 'token': None, 'signature': '242660ea3ab0faad04f639c4f586f34dd48785d44e551919614a076d6ecf8af6', 'account': None}
Jan  4 05:43:41.335610 hostname proxy-server: 150.50.2.135 150.50.2.135 04/Jan/2019/05/43/41 HEAD /v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9 HTTP/1.0 204 - - gAAAAABcLvKM5Eb1... - - a4c2265dec2b9c9c759012f32bbf808b tx78671d8454dd4a89a611a-005c2ef28d - 0.0712 S3 - 1546580621.260189056 1546580621.331365108 0
Jan  4 05:43:41.463117 hostname proxy-server: 150.50.2.135 150.50.2.135 04/Jan/2019/05/43/41 HEAD /v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9/2M_file.file HTTP/1.0 200 - - gAAAAABcLvKM5Eb1... - - a4c2265dec2b9c9c759012f32bbf808b tx78671d8454dd4a89a611a-005c2ef28d - 0.0748 S3 - 1546580621.387617111 1546580621.462440014 0
Jan  4 05:43:41.518929 hostname proxy-server: 150.50.2.135 150.50.2.135 04/Jan/2019/05/43/41 HEAD /v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9/firmimg.d7 HTTP/1.0 200 - - gAAAAABcLvKM5Eb1... - - a4c2265dec2b9c9c759012f32bbf808b tx78671d8454dd4a89a611a-005c2ef28d - 0.0927 S3 - 1546580621.423897982 1546580621.516571999 0
Jan  4 05:43:41.688667 hostname proxy-server: 150.50.2.135 150.50.2.135 04/Jan/2019/05/43/41 DELETE /v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9/2M_file.file HTTP/1.0 204 - - gAAAAABcLvKM5Eb1... - - a4c2265dec2b9c9c759012f32bbf808b tx78671d8454dd4a89a611a-005c2ef28d - 0.1977 S3 - 1546580621.490247965 1546580621.687973976 0


object-server log:
root@VM:~# grep bucket9 /var/log/swift/storage.log
Jan  4 05:43:41.090458 hostname container-server: 150.50.3.137 - - [04/Jan/2019:05:43:41 +0000] "HEAD /volume-00006828/3630/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9" 204 - "HEAD http://vsa-00000ae2-zadara-dev2.zadarazios.com/v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9" "tx79aefa29e485496fa408b-005c2ef28c" "proxy-server 10171" 0.0045 "-" 9927 0
Jan  4 05:43:41.155328 hostname container-server: 150.50.3.137 - - [04/Jan/2019:05:43:41 +0000] "GET /volume-00006828/3630/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9" 200 358 "GET http://vsa-00000ae2-zadara-dev2.zadarazios.com/v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9?format=json&limit=1001" "tx79aefa29e485496fa408b-005c2ef28c" "proxy-server 10171" 0.0150 "-" 9925 0
Jan  4 05:43:41.327503 hostname container-server: 150.50.3.137 - - [04/Jan/2019:05:43:41 +0000] "HEAD /volume-00006828/3630/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9" 204 - "HEAD http://vsa-00000ae2-zadara-dev2.zadarazios.com/v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9" "tx78671d8454dd4a89a611a-005c2ef28d" "proxy-server 10171" 0.0091 "-" 9925 0
Jan  4 05:43:41.492842 hostname object-server: 150.50.3.137 - - [04/Jan/2019:05:43:41 +0000] "HEAD /volume-00006824/22031/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9/firmimg.d7" 200 5177 "HEAD http://vsa-00000ae2-zadara-dev2.zadarazios.com/v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9/firmimg.d7" "tx78671d8454dd4a89a611a-005c2ef28d" "proxy-server 10171" 0.0081 "-" 9704 0
Jan  4 05:43:41.672267 hostname container-server: 150.50.3.137 - - [04/Jan/2019:05:43:41 +0000] "DELETE /volume-00006828/3630/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9/2M_file.file" 204 - "DELETE http://vsa-00000ae2-zadara-dev2.zadarazios.com/volume-00006825/2174/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9/2M_file.file" "tx78671d8454dd4a89a611a-005c2ef28d" "object-server 9163" 0.0035 "-" 9924 0
Jan  4 05:43:41.685755 hostname object-server: 150.50.3.137 - - [04/Jan/2019:05:43:41 +0000] "DELETE /volume-00006825/2174/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9/2M_file.file" 204 - "DELETE http://vsa-00000ae2-zadara-dev2.zadarazios.com/v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9/2M_file.file" "tx78671d8454dd4a89a611a-005c2ef28d" "proxy-server 10171" 0.0966 "-" 9163 0
Jan  4 05:45:26.352897 hostname account-server: 150.50.3.130 - - [04/Jan/2019:05:45:26 +0000] "PUT /volume-00006828/3273/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9" 201 - "-" "-" "container-updater 26119" 0.0014 "-" 8995 0