diff --git a/plugin-designs/doxa-research-map/research-map.vue b/plugin-designs/doxa-research-map/research-map.vue
index 477b7791f..2804f04d5 100644
--- a/plugin-designs/doxa-research-map/research-map.vue
+++ b/plugin-designs/doxa-research-map/research-map.vue
@@ -2321,6 +2321,23 @@ let _emptyRetries = 0
 // first load, or after a clear that has already been reported, empty is simply the truth.
 let _lastEmitWasFilled = false
 function emitFilterStateSettled() {
+  // ★ THE ECHO GUARD MUST BE READ WHEN THE CHANGE HAPPENS, NOT WHEN THE TIMER FIRES.
+  // rega, row 50: a region row click emitted {region:"asia"} and then an EMPTY event, on both
+  // engines. It passed only because the composite's 1.2s push window happened to swallow the
+  // second one — a pass that depends on a swallow is not a pass.
+  //
+  // THE CAUSE IS MINE, AND IT IS THE COALESCING I ADDED. emitFilterState has always opened with
+  // `if (applyingExternal) return`: when the HOST pushes state down through externalFilters, the
+  // store changes, and reporting that back up is an echo of the host's own instruction. That guard
+  // worked because the emit ran SYNCHRONOUSLY inside the watcher, while the flag was still set.
+  // Debouncing moved the emit 60ms later — and applyingExternal is released on nextTick, long
+  // before that — so by the time the emit ran the flag was false and the echo went out. I fixed a
+  // burst and broke a guard that depended on the burst's timing, which is the cost of changing WHEN
+  // something runs without re-reading what else depended on when.
+  //
+  // So the decision is taken here, at schedule time, where the flag still means what it says: a
+  // change that arrived from the host is not a change the reader made, and is not reported back.
+  if (applyingExternal) return
   _emptyRetries = 0          // a fresh user action restarts the budget
   clearTimeout(_emitTimer)
   _emitTimer = setTimeout(emitFilterState, EMIT_SETTLE_MS)
diff --git a/plugin-designs/doxa-research-map/scripts/check-language-code-link.mjs b/plugin-designs/doxa-research-map/scripts/check-language-code-link.mjs
index 0b30de8e4..18eafdef5 100644
--- a/plugin-designs/doxa-research-map/scripts/check-language-code-link.mjs
+++ b/plugin-designs/doxa-research-map/scripts/check-language-code-link.mjs
@@ -278,6 +278,26 @@ if (matchesLanguage) {
   } else notes.push('empty guard: a mid-cascade read is re-taken, a real clear still gets through')
 }
 
+// ── H. the echo guard survives the coalescing ────────────────────────────────────────────────
+// rega, row 50: a region click emitted the selection and then an EMPTY event, passing only because
+// the composite's 1.2s push window swallowed the second. emitFilterState has always opened with
+// `if (applyingExternal) return` — a change pushed DOWN by the host is not a change to report back
+// up — and that worked while the emit ran synchronously inside the watcher. Debouncing moved the
+// emit 60ms later while applyingExternal is released on nextTick, so the flag was already false
+// when the emit ran and the echo went out. The guard has to be read where the change happens.
+{
+  const src = emitterSrc
+  const sched = /function emitFilterStateSettled\(\) \{([\s\S]*?)\n\}/.exec(src)
+  if (!sched) fails.push('H  research-map.vue: emitFilterStateSettled() not found — this gate cannot see whether the echo guard survives the debounce.')
+  // ★ COMMENTS STRIPPED FIRST, and this is the THIRD time the same hole has appeared in my own
+  // checks. The body below explains the fix in prose that QUOTES the line it is asserting, so a
+  // naive search matched the comment and stayed green after the code was deleted. A check that its
+  // own documentation can satisfy is not a check; only executable lines count.
+  else if (!/if \(applyingExternal\) return/.test(sched[1].split('\n').filter((l) => !/^\s*(\/\/|\*|\/\*)/.test(l)).join('\n'))) {
+    fails.push('H  the settle scheduler does not check applyingExternal. The check inside emitFilterState runs 60ms later, and applyingExternal is released on nextTick — so a change the HOST pushed down is reported back up as if the reader had made it. That is an echo, and it reaches the composite as an empty report.')
+  } else notes.push('echo guard: read at schedule time, where applyingExternal still means what it says')
+}
+
 for (const n of notes) console.log('  · ' + n)
 if (fails.length) {
   console.error(`\n${TAG}: FAIL`)