Where it usually breaks
And how to keep it from happening.
- Duplicate stock effect. A lost response should lead to an equivalent retry using the original effect identity. It must not become another quantity posting.
- Wrong comparison basis. Agree how signed quantities and compensating movements enter the request comparison. Inspect the actual postings when the result is unclear.
- Execution accepted without reconciliation. A Recorded receipt preserves an action result. Verification still needs evidence that the posted quantity matches the authorized work.