[HPE] Failed to create multiple instances with boot volumes at the same time in version 20.0.2.dev11.

Description:

Env Info:
HPE 3par 8K
Wsapi: 1.6.15
Image Cache: True

Problem with:
python-3parclient 4.2.12

cinder 20.0.2.dev11

In such a scenario, below errors may occur for some vms:

Error: Failed to perform requested operation on instance "test-10", the instance has an error status: Please try again later [Error: Build of instance 9eb0f656-8401-44b6-9cd0-742bb49ca605 aborted:
Unable to update attachment.(Bad or unexpected response from the storage volume backend API: Driver initialize connection failed (error: Forbidden (HTTP 403) 6 - invalid session key).). (HTTP].

Error list:
Bad or unexpected response from the storage volume backend API: Driver initialize connection failed (error: Forbidden (HTTP 403) 6 - invalid session key).). (HTTP].
or
Exception during message handling: cinder.exception.VolumeBackendAPIException: Bad or unexpected response from the storage volume backend API: Driver initialize connection failed (error: 'NoneType' object has no attribute 'login').
or
Exception during message handling: cinder.exception.VolumeBackendAPIException: Bad or unexpected response from the storage volume backend API: Driver initialize connection failed (error: 'NoneType' object has no attribute 'logout').
or
Exception during message handling: cinder.exception.VolumeBackendAPIException: Bad or unexpected response from the storage volume backend API: Driver initialize connection failed (error: Conflict (HTTP 409) 34 - resource in use).

From Nova perspective:
Instance Status: Error
Volumes Attached To a47805b4-aa00-4e83-80ac-a10e20e865b8 on /dev/vda

From Cinder perspective:
ID: a47805b4-aa00-4e83-80ac-a10e20e865b8
Volume Attached To: Not Attached

Same env/storage with one exception (cinder version):

python-3parclient 4.2.12

cinder 19.1.1

No problem at all.