PB transactions API returns incorrect postingDate for posted transaction #85

Level

High

Describe the bug

Summary

The Investec Private Banking transactions API is returning an incorrect postingDate for a posted transaction.

For the transaction below, both transactionDate and actionDate are 2026-05-04, but postingDate is returned as 2026-05-09, which is the date the API request was made.

Endpoint

GET /za/pb/v1/accounts/{accountId}/transactions

Steps To Reproduce

1. Authenticate against the Investec OpenAPI Private Banking API.
2. Call the Private Banking transactions endpoint for the affected account: GET /za/pb/v1/accounts/{accountId}/transactions.
3. Use a date range that includes 2026-05-04, for example: GET /za/pb/v1/accounts/{accountId}/transactions?fromDate=2026-05-04&toDate=2026-05-09.
4. Inspect the returned transaction matching amount = ***20.63, description = 1001280**** LE JENKINS, type = CREDIT, and status = POSTED.
5. Observe that the returned date fields are transactionDate = 2026-05-04, actionDate = 2026-05-04, and postingDate = 2026-05-09.
6. The postingDate value is 2026-05-09, which was the API request date, while both transactionDate and actionDate are 2026-05-04.
7. Repeat the same request on a later date.
8. Confirmed postingDate changes to the later API request date rather than remaining stable as the actual posting date for the transaction.

Raw API Response

{
  "accountId": "00238127**************",
  "actionDate": "2026-05-04",
  "amount": ***20.63,
  "cardNumber": "",
  "description": "1001280**** LE JENKINS",
  "postedOrder": 0,
  "postingDate": "2026-05-09",
  "runningBalance": -***11.59,
  "status": "POSTED",
  "transactionDate": "2026-05-04",
  "transactionType": null,
  "type": "CREDIT",
  "uuid": "",
  "valueDate": null
}

Expected behaviour

For a transaction with status = POSTED, the postingDate field should represent the actual ledger posting date of the transaction.

The postingDate should be stable across repeated API calls and should not change based on the date the API request is made.

For the transaction shown in the raw API response, both transactionDate and actionDate are 2026-05-04. Unless there is a documented reason for postingDate to differ, the expected postingDate should also be 2026-05-04.

The API should also provide clear documentation on the semantic difference between postingDate, transactionDate, and actionDate, including which field should be treated as the authoritative ledger date for posted transactions.

Actual behaviour

The API returned postingDate = 2026-05-09 for the transaction.

This differs from both transactionDate = 2026-05-04 and actionDate = 2026-05-04.

The postingDate value appears to match the date the API request was made, rather than the actual ledger posting date of the transaction.

Because the transaction has status = POSTED, this makes the returned postingDate misleading for downstream reconciliation and accounting systems.

Additional context

Impact

This breaks downstream accounting reconciliation.

Our sync process uses postingDate as the canonical ledger date. In this case, the API response caused the sync process to attempt to move an existing accounting transaction from 2026-05-04 to 2026-05-09.

That would incorrectly alter the ledger date for a posted transaction, affecting:

• Account reconciliation
• Duplicate detection
• Historical reporting
• Running balance validation
• Auditability of imported bank transactions

Questions

1. For posted transactions, which field should be treated as the authoritative ledger date?
2. Is the empty uuid expected for this transaction type?
3. Is this a known issue with the Private Banking transactions endpoint?