`aws_apigatewayv2_integration`: removing an entry from `request_parameters` fails during in-place update

Terraform v1.15.6
hashicorp/aws v6.65.0
Windows amd64

~ request_parameters = {
    - "DelaySeconds" = "0" -> null
      # (3 unchanged elements hidden)
  }

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

Error: updating API Gateway v2 Integration: operation error ApiGatewayV2:
UpdateIntegration, https response error StatusCode: 400,
BadRequestException: Invalid selection expression specified:
Validation Result: warnings : [], errors :
[Mapping expression missing source or destination]

{
  "integrationSubtype": "SQS-SendMessage",
  "integrationType": "AWS_PROXY",
  "requestParameters": {
    "QueueUrl": "https://sqs.ca-central-1.amazonaws.com/ACCOUNT/QUEUE",
    "MessageBody": "$request.body",
    "Region": "ca-central-1",
    "DelaySeconds": ""
  }
}

{
  "message": "Invalid selection expression specified: Validation Result: warnings : [], errors : [Mapping expression missing source or destination]"
}

resource "aws_apigatewayv2_integration" "repro" {
  api_id                 = aws_apigatewayv2_api.repro.id
  integration_type       = "AWS_PROXY"
  integration_subtype    = "SQS-SendMessage"
  credentials_arn        = aws_iam_role.repro.arn
  payload_format_version = "1.0"

  request_parameters = {
    QueueUrl    = aws_sqs_queue.repro.url
    MessageBody = "$request.body"
    Region      = "ca-central-1"
    DelaySeconds = "0"
  }
}