deregistering kubernetes pods from Consul

I am using a IHostedService to register my pods inside the k8s cluster. It all runs fine but when I need to update or scale my deployments I get zombie pods hanging around in Consul.

My IHostedService implements the StopAsync as follows:

public async Task StopAsync(CancellationToken cancellationToken)
        {
            _cts.Cancel();
            _logger.LogInformation("De-registering from Consul");
            try
            {
                await _consulClient.Agent.ServiceDeregister(_registrationId, cancellationToken);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, $"De-registration failed");
            }
        }

I also tried injecting in IHostApplicationLifetime and registering an ApplicationStopping but it's the same deal - these functions never get called unless I physically press ctrl +c which obviously isn't happening inside k8s

How is everyone deregistering their pods?

I'm using netcore 3.1