diff --git a/plugin-designs/my-upg-100-list/poster-wall.vue b/plugin-designs/my-upg-100-list/poster-wall.vue
index fcc024118..e71fddfbd 100644
--- a/plugin-designs/my-upg-100-list/poster-wall.vue
+++ b/plugin-designs/my-upg-100-list/poster-wall.vue
@@ -39,7 +39,7 @@
  * IDEA-POSTER-EXPORT-404-ON-DROPPED-FOLDER-TRADEOFF.
  */
 import { computed, inject, ref } from 'vue'
-import { useOptionalT } from '@map/composables/useOptionalT.js'
+import { useOptionalT, useOptionalI18n } from '@map/composables/useOptionalT.js'
 // The page's people-group LIST (library/lists/): every people-group fetch below keeps only its groups.
 import { resolvePeopleGroupList } from '@map/lists/peopleGroupList.js'
 import PosterWall from '@map/components/poster/PosterWall.vue'
@@ -151,9 +151,13 @@ const regionFor = (id) => {
 // buildLegendNodes collapses the two deaf_lists into one unified row. This spread still yields 27 because
 // it reads the three geographic buckets and the deaf row is synthesised — so the number is right for what
 // this list IS, and the old comment was describing the wrong thing.
+const { locale: wallLocale } = useOptionalI18n('')
 const items = computed(() => {
   const z = zonesForList(resolvePeopleGroupList(profileConfig))
-  const locale = getRuntimeLocale() || detectLocale()
+  // The i18n locale REF, read here so this computed re-runs on a runtime language switch: getRuntimeLocale()
+  // is a plain getter, and a computed that reads only it is resolved once and never again (a frozen label).
+  const l = wallLocale && (wallLocale.value ?? wallLocale)
+  const locale = (typeof l === 'string' && l) || getRuntimeLocale() || detectLocale()
   return [
     ...(z.lists || []),
     ...(z.asia_lists || []),
diff --git a/plugin-designs/my-upg-100-list/upg-100-list.vue b/plugin-designs/my-upg-100-list/upg-100-list.vue
index 6b4cb0183..8e98410e3 100644
--- a/plugin-designs/my-upg-100-list/upg-100-list.vue
+++ b/plugin-designs/my-upg-100-list/upg-100-list.vue
@@ -417,7 +417,9 @@ const { locale: packetLocale, t } = useI18n()
 // The first status a reader sees. Set in a watcher, not once at setup, so a language switch while the
 // map is still loading re-resolves it; the first real status replaces it and the watcher then leaves it.
 let loadingText = ''
-watch(packetLocale, () => {
+// Watched through packetLang(), not packetLocale itself: the host may install i18n with a plain-string
+// locale (see packetLang), and watch() on a non-ref is an invalid source that never fires.
+watch(() => packetLang(), () => {
   if (status.value === '' || status.value === loadingText) status.value = loadingText = t('legend.loadingData')
 }, { immediate: true })
 
@@ -438,6 +440,24 @@ function legendOpts(records) {
     regionTitle: (english) => (REGION_KEY[english] ? t(`poster.${REGION_KEY[english]}`) : english),
   }
 }
+// ★ AND RE-BUILT WHEN THE LANGUAGE CHANGES. The tree above is built once and STORED, so a runtime switch
+// (ProfileLoader drives the i18n locale mid-session) left every region and zone name in the boot language
+// while the chrome around it changed — a frozen label that check:frozen-labels cannot see, because t()
+// runs inside a function. One builder for all three build sites remembers the last records, and a watch
+// on the locale rebuilds the tree, relabels the flat zone list IN PLACE (colours and selectors stay), and
+// refreshes the search feed built from those labels.
+let legendRecords = null
+function buildLegend(records) {
+  if (records !== undefined) legendRecords = records
+  return buildLegendNodes(listZones(), legendOpts(legendRecords))
+}
+watch(() => packetLang(), () => {
+  if (!legendNodes.value.length) return
+  legendNodes.value = buildLegend()
+  const fresh = new Map(leafZones(legendNodes.value).map((l) => [l.id, l.label]))
+  for (const z of leafZoneList) if (fresh.has(z.id)) z.label = fresh.get(z.id)
+  if (searchRecords) buildSearch(searchRecords)
+})
 // ⚠ IT WAS A HARDCODED ENGLISH LITERAL, and SemanticTreeLegend passes `title` through RAW —
 // the caller owns localizing it. MEASURED 2026-09-25 on the live Chinese render: the legend
 // header read "My UPG 100 List — Legend" in full English inside an otherwise localized panel,
@@ -952,7 +972,9 @@ function clearSelection() {
 // useGeoSearch consumes; zone rows from the legend leafZones; territory rows
 // from admin-counts (ADM1) + ISO3 names (ADM0 countries). countryNameMap (built
 // from the live records) gives the exact country label the legend shows.
+let searchRecords = null                      // the records the feed was last built from (see the locale watch)
 function buildSearch(records) {
+  searchRecords = records
   // (i) Feed the SHARED GeocoderComponent: unify PG + zone + territory into ONE
   //     record list and cache it under our source so useGeoSearch (inside the
   //     component) indexes it. Zones/territories ride as synthetic records with a
@@ -2162,7 +2184,7 @@ function bootstrapLegend() {
   // the two would disagree with nothing reporting it. Found by grepping for `clusters.` rather than by
   // trusting the convention comment.
   const z = listZones()
-  const nodes = buildLegendNodes(z, legendOpts(null))
+  const nodes = buildLegend(null)
   legendNodes.value = nodes
   leafZoneList = leafZones(nodes)
   const byId = {}
@@ -2193,7 +2215,7 @@ async function enrichLegendFromRecords() {
     if (!resp.ok) throw new Error(`list ${resp.status}`)
     const records = normalizeRecords(await applyPeopleGroupList(extractRecords(await resp.json()), profileConfig))
     countryNameMap = buildCountryNameMap(records)
-    legendNodes.value = buildLegendNodes(listZones(), legendOpts(records))
+    legendNodes.value = buildLegend(records)
   } catch (_) { /* counts-only legend is the honest fallback; keep it rendered */ }
 }
 
@@ -2556,7 +2578,7 @@ onMounted(async () => {
 
     // Re-shape the legend tree WITH records so every node carries `pop` (slice
     // 04u §1b). Selectors/colors/counts are unchanged; only `pop` is added.
-    legendNodes.value = buildLegendNodes(listZones(), legendOpts(records))
+    legendNodes.value = buildLegend(records)
 
 
     // ── pins layer (kept from 04b, now stamped with zoneKey for isolate dim) ──