diff --git a/apps/edr-freight-api/src/modules/billing/eims-invoice.mapper.spec.ts b/apps/edr-freight-api/src/modules/billing/eims-invoice.mapper.spec.ts
index 6d58a7bec..75d39a500 100644
--- a/apps/edr-freight-api/src/modules/billing/eims-invoice.mapper.spec.ts
+++ b/apps/edr-freight-api/src/modules/billing/eims-invoice.mapper.spec.ts
@@ -151,7 +151,9 @@ describe("toEimsInvoice", () => {
       // EimsLineTax.discount comment in eims-invoice.mapper.ts.
       Discount: 25,
       TotalLineAmount: 1050,
-      Unit: "CTR",
+      // Not "CTR" from the line's metadata.unit — that's our internal fee-basis tag, not a MoR
+      // unit of measure, and is never read for this field (see the mapper's own comment).
+      Unit: "PCS",
     });
     expect(doc.ValueDetails).toEqual({
       Discount: null,
diff --git a/apps/edr-freight-api/src/modules/billing/eims-invoice.mapper.ts b/apps/edr-freight-api/src/modules/billing/eims-invoice.mapper.ts
index b8755c709..c72e61c7a 100644
--- a/apps/edr-freight-api/src/modules/billing/eims-invoice.mapper.ts
+++ b/apps/edr-freight-api/src/modules/billing/eims-invoice.mapper.ts
@@ -463,7 +463,13 @@ export function toEimsInvoice(
     const PreTaxValue = round2(num(line.amount));
     const TaxAmount = round2((PreTaxValue * tax.ratePercent) / 100);
     const ExciseTaxValue = round2(tax.exciseTaxValue);
-    const unit = typeof line.metadata?.unit === "string" ? line.metadata.unit : context.unitDefault;
+    // `line.metadata.unit` is our own fee-basis tag (PER_CONTAINER/PER_TON/PER_ITEM — how a charge
+    // is computed, see the fee-rule docs), never a MoR unit of measure — sending it as-is here
+    // (confirmed live 2026-08-17: "PER_CONTAINER" fails Unit's enum, its 8-char max, and its regex
+    // all at once) is what a prior version of this mapper did by mistake. MoR's own enum
+    // (LTR/MTR/101/PCS/ROL/MTS/PKG/SET/KLG) has no freight-shipment concept at all, so every line
+    // uses the single configured default rather than guessing a per-line value that doesn't exist.
+    const unit = context.unitDefault;
 
     return {
       Discount: round2(tax.discount),