diff --git a/apps/backoffice/src/app/features/certificate-designer/components/DesignerToolbar.tsx b/apps/backoffice/src/app/features/certificate-designer/components/DesignerToolbar.tsx
index 4ab644bc6..c34a1e368 100644
--- a/apps/backoffice/src/app/features/certificate-designer/components/DesignerToolbar.tsx
+++ b/apps/backoffice/src/app/features/certificate-designer/components/DesignerToolbar.tsx
@@ -84,9 +84,11 @@ export function DesignerToolbar({
             <Text size="sm" fw={600}>
               {validityDays != null
                 ? t('designer.validityDays', '{{count}} days', { count: validityDays })
-                : t('designer.validityMonths', '{{count}} months', {
-                    count: validityMonths,
-                  })}
+                : validityMonths
+                  ? t('designer.validityMonths', '{{count}} months', {
+                      count: validityMonths,
+                    })
+                  : t('designer.validityNone', 'Does not expire')}
             </Text>
             <Text size="xs" c="dimmed">
               {t('designer.validityEditedOn', '— set on Certificate Requirements → Behaviour')}
diff --git a/apps/backoffice/src/app/features/certificate-requirements/components/BehaviorTab.tsx b/apps/backoffice/src/app/features/certificate-requirements/components/BehaviorTab.tsx
index 891acfc15..d1606b697 100644
--- a/apps/backoffice/src/app/features/certificate-requirements/components/BehaviorTab.tsx
+++ b/apps/backoffice/src/app/features/certificate-requirements/components/BehaviorTab.tsx
@@ -72,9 +72,13 @@ function toDraft(licenseType: LicenseType): Draft {
       licenseType.capitalThreshold == null
         ? null
         : Number(licenseType.capitalThreshold),
+    // Zero is a real stored state for `validityMonths` (a type that issues
+    // nothing with an expiry) and is kept. Zero in the other two is not a
+    // policy anyone set — it is an unfilled column — and seeding a box with a
+    // value below its own floor only produces a save the server rejects.
     validityMonths: licenseType.validityMonths ?? 12,
-    validityDays: licenseType.validityDays ?? null,
-    renewalWindowDays: licenseType.renewalWindowDays ?? 60,
+    validityDays: licenseType.validityDays || null,
+    renewalWindowDays: licenseType.renewalWindowDays || 60,
     expiryReminderDays: licenseType.expiryReminderDays ?? [60, 30, 7],
     requiresOperatorMode: licenseType.requiresOperatorMode ?? true,
     allowMultipleOpenDrafts: licenseType.allowMultipleOpenDrafts ?? false,
@@ -128,9 +132,38 @@ export function BehaviorTab({ licenseType }: { licenseType: LicenseType }) {
   // against an expiry that never arrives, so none of them are asked for.
   const expires = draft.validityDays !== null || draft.validityMonths > 0;
 
+  // The server's floor for a stated term is 6 months, so no-expiry is a state
+  // this form can hold and edit around but cannot switch a type into. Offered
+  // only where it is already what the type is, rather than as an option whose
+  // save would be refused.
+  const noExpiryAvailable =
+    (licenseType.validityMonths ?? 12) === 0 && !licenseType.validityDays;
+
   async function onSave() {
+    // Only the settings this form actually asked for. The endpoint patches, so
+    // an omitted field keeps its stored value — and the fields hidden above are
+    // hidden precisely because the type has no such policy, which the server
+    // stores as a zero its own validators then refuse (`validityMonths` has a
+    // floor of 6, `renewalWindowDays` of 1). Echoing those back is what made
+    // saving an ownership transfer fail outright.
+    const {
+      validityMonths,
+      validityDays,
+      renewalWindowDays,
+      expiryReminderDays,
+      ...rest
+    } = draft;
+
     const ok = await run(
-      () => save({ id: licenseType.id, ...draft }).unwrap(),
+      () =>
+        save({
+          id: licenseType.id,
+          ...rest,
+          ...(expires ? { validityMonths, validityDays } : {}),
+          ...(expires && draft.renewalEnabled
+            ? { renewalWindowDays, expiryReminderDays }
+            : {}),
+        }).unwrap(),
       t('certReq.behavior.saved', 'Configuration saved.'),
     );
     if (ok) setDirty(false);
@@ -334,7 +367,14 @@ export function BehaviorTab({ licenseType }: { licenseType: LicenseType }) {
             data={[
               { value: 'MONTHS', label: t('certReq.behavior.unitMonths', 'Months') },
               { value: 'DAYS', label: t('certReq.behavior.unitDays', 'Days') },
-              { value: 'NONE', label: t('certReq.behavior.unitNone', 'Does not expire') },
+              ...(noExpiryAvailable
+                ? [
+                    {
+                      value: 'NONE',
+                      label: t('certReq.behavior.unitNone', 'Does not expire'),
+                    },
+                  ]
+                : []),
             ]}
             value={
               draft.validityDays !== null
diff --git a/apps/backoffice/src/app/i18n/locales/am.ts b/apps/backoffice/src/app/i18n/locales/am.ts
index 543417370..5b6e36fbe 100644
--- a/apps/backoffice/src/app/i18n/locales/am.ts
+++ b/apps/backoffice/src/app/i18n/locales/am.ts
@@ -1253,6 +1253,7 @@ export const am: Translations = {
     validityMonths_other: "{{count}} ወራት",
     validityDays_one: "{{count}} ቀን",
     validityDays_other: "{{count}} ቀናት",
+    validityNone: "ጊዜው አያልፍም",
     validityEditedOn: "— በምስክር ወረቀት መስፈርቶች → ባህሪ ውስጥ ይዘጋጃል",
     newVersion: "አዲስ ስሪት",
     versions: "ስሪቶች",
diff --git a/apps/backoffice/src/app/i18n/locales/en.ts b/apps/backoffice/src/app/i18n/locales/en.ts
index a3aed8a28..efe91b783 100644
--- a/apps/backoffice/src/app/i18n/locales/en.ts
+++ b/apps/backoffice/src/app/i18n/locales/en.ts
@@ -1260,6 +1260,7 @@ export const en = {
     validityMonths_other: '{{count}} months',
     validityDays_one: '{{count}} day',
     validityDays_other: '{{count}} days',
+    validityNone: 'Does not expire',
     validityEditedOn: '— set on Certificate Requirements → Behaviour',
     newVersion: 'New version',
     versions: 'Versions',
diff --git a/apps/portal/src/app/features/licensing/components/LicenseCatalogue.tsx b/apps/portal/src/app/features/licensing/components/LicenseCatalogue.tsx
index c948e5e58..189eb8f00 100644
--- a/apps/portal/src/app/features/licensing/components/LicenseCatalogue.tsx
+++ b/apps/portal/src/app/features/licensing/components/LicenseCatalogue.tsx
@@ -322,8 +322,16 @@ function LicenseTypeCard({
               </Tooltip>
             )}
             {type.issuesCertificate ? (
+              // A term in days wins over the months column, and a type with
+              // neither issues something that simply does not expire — a
+              // transfer, or any one-off record. Reading `validityMonths`
+              // alone badged those "0 months".
               <Badge size="sm" variant="light" color="teal">
-                {t('licensing.catalogue.validityBadge', { months: type.validityMonths })}
+                {type.validityDays
+                  ? t('licensing.catalogue.validityDaysBadge', { count: type.validityDays })
+                  : type.validityMonths
+                    ? t('licensing.catalogue.validityBadge', { months: type.validityMonths })
+                    : t('licensing.catalogue.noExpiryBadge')}
               </Badge>
             ) : (
               <Tooltip label={t('licensing.catalogue.evaluationTooltip')}>
diff --git a/apps/portal/src/app/i18n/locales/am.ts b/apps/portal/src/app/i18n/locales/am.ts
index fdc789666..a52fe60b6 100644
--- a/apps/portal/src/app/i18n/locales/am.ts
+++ b/apps/portal/src/app/i18n/locales/am.ts
@@ -884,6 +884,9 @@ export const am: Translations = {
       capitalTooltip: 'በባንክ ደብዳቤ መረጋገጥ ያለበት ዝቅተኛ ካፒታል',
       capitalBadge: 'ካፒታል {{amount}}',
       validityBadge: '{{months}} ወራት',
+      validityDaysBadge_one: '{{count}} ቀን',
+      validityDaysBadge_other: '{{count}} ቀናት',
+      noExpiryBadge: 'ጊዜው አያልፍም',
       evaluationTooltip: 'በምስክር ወረቀት ፈንታ በባለሥልጣኑ ውሳኔ የሚጠናቀቅ',
       evaluationOnly: 'ግምገማ ብቻ',
       startApplication: 'ማመልከቻ ጀምር',
diff --git a/apps/portal/src/app/i18n/locales/en.ts b/apps/portal/src/app/i18n/locales/en.ts
index 3e52108bb..14ba1720c 100644
--- a/apps/portal/src/app/i18n/locales/en.ts
+++ b/apps/portal/src/app/i18n/locales/en.ts
@@ -886,6 +886,9 @@ export const en = {
       capitalTooltip: 'Minimum capital that must be evidenced by a bank letter',
       capitalBadge: 'Capital {{amount}}',
       validityBadge: '{{months}} months',
+      validityDaysBadge_one: '{{count}} day',
+      validityDaysBadge_other: '{{count}} days',
+      noExpiryBadge: 'No expiry',
       evaluationTooltip: 'Concludes with an EMA decision rather than a certificate',
       evaluationOnly: 'Evaluation only',
       startApplication: 'Start application',