Hi,
This behaviour is due to the fact that LEDGER_ITEM_CU_DET_QRY doesn’t have a base table behind it. It’s a query‑based LU that pulls information from other areas of IFS (for example LEDGER_ITEM_AUTH, voucher tables, posting control, etc...).
Because there’s no underlying table, IFS can’t store persistent custom field values against this LU so while you can create a persistent field, the client can’t insert or update anything.
Read‑only custom fields work fine because the _CFV view is just extending the query and returning data, not storing it.
If you need to store additional information, you’d need to add the persistent field to the LU where the data actually lives, and then expose it in LEDGER_ITEM_CU_DET_QRY as a read‑only field?
Alternatively, you could create a small custom LU/table to hold your invoice‑query metadata (e.g., keyed by Company, Invoice No, Series ID) and then join or reference that data in the Ledger Item query. This would give Credit Control visibility without trying to write into a read‑only LU although it’s a slightly larger piece of work.
Thanks,
R