Unifier API: Incomplete Data Insertion Despite Success Response

We're performing an integration using the Unifier API to send measurement data to a specific Business Process (BP). We're using the /ws/rest/service/v1/bp/record/ endpoint to submit a JSON payload that should insert line items into the BP.

However, we've found that some lines are not being correctly stored when the complete payload is sent. For example, item 5.2.4 has a quantity of zero in Unifier, even though the data was clearly sent via the API in the payload. If we send only the value for item 5.2.4 in a separate request, it's inserted correctly.

The API consistently returns a success message, yet some lines are still not being inserted. I've opened a Service Request with support, and the response suggested we send less than 2,000 lines per request. However, I have already limited our requests to 1,000 lines, so this does not appear to be the root cause.