diff --git a/packages/core/src/runtime/webAudioTransport.test.ts b/packages/core/src/runtime/webAudioTransport.test.ts
index 15f1825a13..f1597ccc8b 100644
--- a/packages/core/src/runtime/webAudioTransport.test.ts
+++ b/packages/core/src/runtime/webAudioTransport.test.ts
@@ -388,6 +388,19 @@ describe("WebAudioTransport", () => {
       expect(transport.isActive()).toBe(false);
     });
 
+    it("disposes the FX graph when a clip ends naturally", async () => {
+      // stopAll() disposes by walking _activeSources, and the splice above had
+      // already removed this entry — so the handle, its MutationObserver and any
+      // running LFO survived the clip for the rest of the session.
+      const { transport, mock, gen } = setupTransport(100);
+      await transport.schedulePlayback(mockEl, mockBuffer, 0, 0, 0, 1, gen);
+
+      mock.sourceNode._fireEnded();
+
+      expect(mock.sourceNode.disconnect).toHaveBeenCalled();
+      expect(mock.gainNode.disconnect).toHaveBeenCalled();
+    });
+
     it("registers onended listener on the sourceNode", async () => {
       const { transport, mock, gen } = setupTransport(100);
 
diff --git a/packages/core/src/runtime/webAudioTransport.ts b/packages/core/src/runtime/webAudioTransport.ts
index fedcdca0bf..2ce3ea4bba 100644
--- a/packages/core/src/runtime/webAudioTransport.ts
+++ b/packages/core/src/runtime/webAudioTransport.ts
@@ -243,6 +243,21 @@ export class WebAudioTransport {
         if (idx !== -1) {
           this._activeSources.splice(idx, 1);
           el.muted = priorMuted;
+          // The graph goes with it. Splicing alone left the FX handle alive and
+          // then UNREACHABLE — stopAll() disposes by walking this array, which
+          // the splice just emptied of this entry. Every clip that finished
+          // naturally leaked its MutationObserver for the session, and each one
+          // still answered later `data-fx-chain` edits by rebuilding a whole
+          // graph (impulse response, chorus/phaser oscillators started and never
+          // stopped) around a dead source. Not disposed when idx is -1: stopAll()
+          // has already done it, and `stop()` is what fired this event.
+          try {
+            sourceNode.disconnect();
+            fx?.dispose();
+            gainNode.disconnect();
+          } catch {
+            // Already torn down.
+          }
           if (this._activeSources.length === 0) this._paused = true;
         }
       });