Noticed the same trace last week, FWIW it looks like the only other hit of this:

Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi [None req-32db6b3c-9a3a-4096-9a24-eb277229d52a tempest-ImportImagesTest-1427548021 tempest-ImportImagesTest-1427548021] Caught error: [errno 116] error removing image: rbd.OSError: [errno 116] error removing image
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi Traceback (most recent call last):
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/opt/stack/glance/glance/common/wsgi.py", line 1348, in __call__
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     request, **action_args)
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/opt/stack/glance/glance/common/wsgi.py", line 1391, in dispatch
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     return method(*args, **kwargs)
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/opt/stack/glance/glance/common/utils.py", line 416, in wrapped
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     return func(self, req, *args, **kwargs)
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/opt/stack/glance/glance/api/v2/images.py", line 524, in delete
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     image.delete()
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/opt/stack/glance/glance/domain/proxy.py", line 194, in delete
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     self.base.delete()
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/opt/stack/glance/glance/domain/proxy.py", line 194, in delete
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     self.base.delete()
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/opt/stack/glance/glance/api/policy.py", line 177, in delete
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     return self.image.delete()
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/opt/stack/glance/glance/domain/proxy.py", line 194, in delete
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     self.base.delete()
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/opt/stack/glance/glance/location.py", line 442, in delete
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     location)
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/opt/stack/glance/glance/common/store_utils.py", line 130, in delete_image_location_from_backend
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     safe_delete_from_backend(context, image_id, location)
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/opt/stack/glance/glance/common/store_utils.py", line 59, in safe_delete_from_backend
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     context=context)
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/usr/local/lib/python3.6/dist-packages/glance_store/multi_backend.py", line 509, in delete
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     return store.delete(loc, context=context)
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/usr/local/lib/python3.6/dist-packages/glance_store/capabilities.py", line 176, in op_checker
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     return store_op_fun(store, *args, **kwargs)
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/usr/local/lib/python3.6/dist-packages/glance_store/_drivers/rbd.py", line 619, in delete
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     self._delete_image(target_pool, loc.image, loc.snapshot)
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "/usr/local/lib/python3.6/dist-packages/glance_store/_drivers/rbd.py", line 447, in _delete_image
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi     rbd.RBD().remove(ioctx, image_name)
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi   File "rbd.pyx", line 1281, in rbd.RBD.remove
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi rbd.OSError: [errno 116] error removing image
Jul 29 02:51:31.052677 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: ERROR glance.common.wsgi 
Jul 29 02:51:31.056332 ubuntu-bionic-rax-iad-0018926068 glance-api[48503]: INFO eventlet.wsgi.server [None req-32db6b3c-9a3a-4096-9a24-eb277229d52a tempest-ImportImagesTest-1427548021 tempest-ImportImagesTest-1427548021]

https://826debf165218b1499f4-13270c601ca2148a93462eeebb4d313b.ssl.cf5.rackcdn.com/673341/54/check/nova-ceph-multistore/0709ecf/controller/logs/screen-g-api.txt