Unity with Openstack Cinder

I have Unity 680F integrated with Openstack cinder driver.  The version of the cinder is 15.6.0.  According to the customer, they have turned on the image cache option in the openstack.  They have noticed they cannot create more than 10 image cache using Unity as backend.  My understanding is this image cache is either using Unity thin clone or snapshot feature.

image_volume_cache_enabled = True

image_volume_cache_max_size_gb = 500

image_volume_cache_max_count = 50