That is strange, there really is no X-Amz-Date: 20190513T205322Z in the request. That is what I see when I do the equivalent command
Can you paste the result of rclone config show Wasabi (XXX out the access_key_id and secret_access_key).
I suspect that is the problem, you want to be using v4 auth which is the default.
My wasabi config looks like this
[wasabi]
type = s3
env_auth = false
access_key_id = XXX
secret_access_key = XXX
region =
endpoint = s3.wasabisys.com
location_constraint =
acl =
server_side_encryption =
storage_class =