digitalocean_volume refuses to delete attached volume in destroy action about terraform-provider-digitalocean HOT 2 CLOSED

=== RUN   TestAccDigitalOceanVolume_Droplet
--- FAIL: TestAccDigitalOceanVolume_Droplet (54.61s)
	testing.go:492: Error destroying resource! WARNING: Dangling resources
		may exist. The full state and error is shown below.
		
		Error: Error applying: 1 error(s) occurred:
		
		* digitalocean_volume.foobar (destroy): 1 error(s) occurred:
		
		* digitalocean_volume.foobar: Error deleting volume: DELETE https://api.digitalocean.com/v2/volumes/7ae3de6e-6069-11e7-a457-0242ac110305: 409 A volume that's attached to a Droplet cannot be deleted. Please detach it first before deleting.
		
		State: digitalocean_volume.foobar:
		  ID = 7ae3de6e-6069-11e7-a457-0242ac110305
		  description = peace makes plenty
		  droplet_ids.# = 1
		  droplet_ids.1415892463 = 53916120
		  name = volume-cskjsz0hqg
		  region = nyc1
		  size = 100

The first occurrence was seen at 5:44 PM EDT.
The previous clean up that was a success (hence not affected by the new issue) was at 4:36 PM EDT.

curl -X DELETE -H "Content-Type: application/json" -H "Authorization: Bearer <token>" "https://api.digitalocean.com/v2/droplets/53112244"
curl -X DELETE -H "Content-Type: application/json" -H "Authorization: Bearer <token>" "https://api.digitalocean.com/v2/volumes/938b3d10-5ade-11e7-91b8-0242ac116405"


The output (it worked after 3-4 secs)

22:29 $ curl -X DELETE -H "Content-Type: application/json" -H "Authorization: Bearer <token>" "https://api.digitalocean.com/v2/droplets/53112244"

✔ ~ 
22:31 $ curl -X DELETE -H "Content-Type: application/json" -H "Authorization: Bearer <token>" "https://api.digitalocean.com/v2/volumes/938b3d10-5ade-11e7-91b8-0242ac116405"

{"id":"Illegal Action","message":"A volume that's attached to a Droplet cannot be deleted. Please detach it first before deleting."}✔ ~ 
22:31 $ 
✔ ~ 
22:31 $ 
✔ ~ 
22:31 $ curl -X DELETE -H "Content-Type: application/json" -H "Authorization: Bearer <token>" "https://api.digitalocean.com/v2/volumes/938b3d10-5ade-11e7-91b8-0242ac116405"
{"id":"Illegal Action","message":"A volume that's attached to a Droplet cannot be deleted. Please detach it first before deleting."}

✔ ~ 
22:31 $ curl -X DELETE -H "Content-Type: application/json" -H "Authorization: Bearer <token>" "https://api.digitalocean.com/v2/volumes/938b3d10-5ade-11e7-91b8-0242ac116405"
✔ ~