Transient error. Retry issue when calling GVault Create Hold API

Question

We use the GVault Hold API to create holds in GVault on behalf of our customers using the API defined here https://developers.google.com/vault/reference/rest/v1/matters.holds/create, via the Google.Apis.Vault.v1 Nuget package for .NET (version 1.49.0.2171).

We have a specific customer that, when we call VaultService.Matters.Holds.Create.ExecuteAsync (which calls the above HTTP API as I understand), we're consistently getting back 13 for the response status code, and the status message is "Transient error. Retry". No matter how many times we attempt to create or update the hold, however, we get this same response back. The code that wraps the call to the API is wrapped in exponential backoff logic, so we'll retry up to 5 times with progressively longer delays between each retry before finally stopping and logging the error out.

Is it possible that there's something specific with this customer's workspace? Our other customers are not experiencing this issue. Is there any guidance that you can provide for solving this issue?

Thanks in advance!!!

Basic idea of what we're doing

hold.Accounts = accounts; // The accounts being added to the hold
return await _vaultService // This is our initialized GoogleVaultClient instance
  .Matters
  .Holds
  .Create(hold, matterId)
  .ExecuteAsync();