diff --git a/packages/SystemUI/utils/kairos/src/com/android/systemui/kairos/internal/BuildScopeImpl.kt b/packages/SystemUI/utils/kairos/src/com/android/systemui/kairos/internal/BuildScopeImpl.kt
index 87897d8..86f35f7 100644
--- a/packages/SystemUI/utils/kairos/src/com/android/systemui/kairos/internal/BuildScopeImpl.kt
+++ b/packages/SystemUI/utils/kairos/src/com/android/systemui/kairos/internal/BuildScopeImpl.kt
@@ -36,6 +36,7 @@
 import com.android.systemui.kairos.internal.util.childScope
 import com.android.systemui.kairos.internal.util.mapValuesParallel
 import com.android.systemui.kairos.launchEffect
+import com.android.systemui.kairos.mergeLeft
 import com.android.systemui.kairos.util.Just
 import com.android.systemui.kairos.util.Maybe
 import com.android.systemui.kairos.util.None
@@ -85,7 +86,6 @@
     ): TFlow<A> {
         var job: Job? = null
         val stopEmitter = newStopEmitter()
-        val handle = this.job.invokeOnCompletion { stopEmitter.emit(Unit) }
         // Create a child scope that will be kept alive beyond the end of this transaction.
         val childScope = coroutineScope.childScope()
         lateinit var emitter: Pair<T, S>
@@ -97,7 +97,6 @@
                         reenterBuildScope(this@BuildScopeImpl, childScope).runInBuildScope {
                             launchEffect {
                                 builder(emitter.second)
-                                handle.dispose()
                                 stopEmitter.emit(Unit)
                             }
                         }
@@ -108,7 +107,7 @@
                 },
             )
         emitter = constructFlow(inputNode)
-        return with(frpScope) { emitter.first.takeUntil(stopEmitter) }
+        return with(frpScope) { emitter.first.takeUntil(mergeLeft(stopEmitter, endSignal)) }
     }
 
     private fun <T> tFlowInternal(builder: suspend FrpProducerScope<T>.() -> Unit): TFlow<T> =
@@ -299,12 +298,14 @@
         childScope.coroutineContext.job.invokeOnCompletion { stopEmitter.emit(Unit) }
         // Ensure that once this transaction is done, the new child scope enters the completing
         // state (kept alive so long as there are child jobs).
-        scheduleOutput(
-            OneShot {
-                // TODO: don't like this cast
-                (childScope.coroutineContext.job as CompletableJob).complete()
-            }
-        )
+        // TODO: need to keep the scope alive if it's used to accumulate state.
+        //  Otherwise, stopEmitter will emit early, due to the call to complete().
+        //        scheduleOutput(
+        //            OneShot {
+        //                // TODO: don't like this cast
+        //                (childScope.coroutineContext.job as CompletableJob).complete()
+        //            }
+        //        )
         return BuildScopeImpl(
             stateScope = StateScopeImpl(evalScope = stateScope.evalScope, endSignal = stopEmitter),
             coroutineScope = childScope,
diff --git a/packages/SystemUI/utils/kairos/test/com/android/systemui/kairos/KairosTests.kt b/packages/SystemUI/utils/kairos/test/com/android/systemui/kairos/KairosTests.kt
index 7294ef3..688adae 100644
--- a/packages/SystemUI/utils/kairos/test/com/android/systemui/kairos/KairosTests.kt
+++ b/packages/SystemUI/utils/kairos/test/com/android/systemui/kairos/KairosTests.kt
@@ -1300,6 +1300,26 @@
     }
 
     @Test
+    fun buildScope_stateAccumulation() = runFrpTest { network ->
+        val input = network.mutableTFlow<Unit>()
+        var observedCount: Int? = null
+        activateSpec(network) {
+            val (c, j) = asyncScope { input.fold(0) { _, x -> x + 1 } }
+            deferredBuildScopeAction { c.get().observe { observedCount = it } }
+        }
+        runCurrent()
+        assertEquals(0, observedCount)
+
+        input.emit(Unit)
+        runCurrent()
+        assertEquals(1, observedCount)
+
+        input.emit(Unit)
+        runCurrent()
+        assertEquals(2, observedCount)
+    }
+
+    @Test
     fun effect() = runFrpTest { network ->
         val input = network.mutableTFlow<Unit>()
         var effectRunning = false