total_amount_micros can't be set or updated

Hello.

This issue is happening on V6, and I couldn't seem to find any way to work around this, as both creating a new budget and updating one while setting total_amount_micros both fail with error "The error code is not in this version."

The code below is the minimum reproduction I could make of this.

                budget_operation = client.operation.update_resource.campaign_budget(budget_resource_name) do |budget|
                    budget.total_amount_micros = req.total_amount_micros
                end

                response = client.service.campaign_budget.mutate_campaign_budgets(
                    customer_id: customer_id,
                    operations: [budget_operation],
                )

Thanks.

Start by reproducing the V6 failure using the shown campaign_budget update operation and the mutate_campaign_budgets call, then inspect the client path that handles total_amount_micros and the reported error code. Done means creating and updating a budget with total_amount_micros succeeds without "The error code is not in this version."