Work Order Close Error's -- Pending Transactions

Scenario & Issue Summary
We’re working with a drug manufacturer whose items are configured with Cost Enabled = N and Asset Value = N. Because they’re still in clinical trials, everything is expensed—no costing—and they’ve operated this way for several years. As they prepare for commercialization, we’ve now enabled costing.

During testing, work orders for expensed items (all inputs and outputs with Cost = N) are failing at Work Order Close. Since the items are non-costed and non-asset, the WIP material issues and completions never flow into costing, and no accounting distributions are created. I was surprised to see Work Order Close interfacing to costing even though the output item is non-costed. Any insights into why we’re seeing Work Order Close errors for Pending Transactions?