AWS global accelerator endpoint group traffic_dial_percentage

Anyone able to successfully set a new or existing endpoint group to have a traffic_dial_percentage = 0? I’ve tried various versions of 0 (0.0,0.000) but nothing is working. The apply says it made the change, but it never does:

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  ~ aws_globalaccelerator_endpoint_group.ap-southeast-1
      traffic_dial_percentage: "100" => "0"


Plan: 0 to add, 1 to change, 0 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

aws_globalaccelerator_endpoint_group.ap-southeast-1: Modifying... (ID: arn:aws:globalaccelerator::zzzz...r/fff/endpoint-group/0fe0a6ba1c00)
  traffic_dial_percentage: "100" => "0"
aws_globalaccelerator_endpoint_group.ap-southeast-1: Still modifying... (ID: arn:aws:globalaccelerator::zzzz...r/fff/endpoint-group/0fe0a6ba1c00, 10s elapsed)
aws_globalaccelerator_endpoint_group.ap-southeast-1: Still modifying... (ID: arn:aws:globalaccelerator::zzzz...r/fff/endpoint-group/0fe0a6ba1c00, 20s elapsed)
aws_globalaccelerator_endpoint_group.ap-southeast-1: Modifications complete after 27s (ID: arn:aws:globalaccelerator::zzzz...r/fff/endpoint-group/0fe0a6ba1c00)

Apply complete! Resources: 0 added, 1 changed, 0 destroyed.

Unfortunately the dial remains at 100. We are using version 2.33 of the AWS provider. Any ideas? Thanks in advance.