diff --git a/blink/renderer/modules/webaudio/analyser_node.cc b/blink/renderer/modules/webaudio/analyser_node.cc
index 7e4099b18aee441f128c00f1baa7aa4499f394d9..4881bd090e93634b706273585cb46c2644de4abb 100644
--- a/blink/renderer/modules/webaudio/analyser_node.cc
+++ b/blink/renderer/modules/webaudio/analyser_node.cc
@@ -54,9 +54,14 @@ AnalyserHandler::~AnalyserHandler() {
 }
 
 void AnalyserHandler::Process(uint32_t frames_to_process) {
-  AudioBus* output_bus = Output(0).Bus();
+  DCHECK(Context()->IsAudioThread());
 
-  if (!IsInitialized()) {
+  // It's possible that output is not connected. Assign nullptr to indicate
+  // such case.
+  AudioBus* output_bus = Output(0).RenderingFanOutCount() > 0
+      ? Output(0).Bus() : nullptr;
+
+  if (!IsInitialized() && output_bus) {
     output_bus->Zero();
     return;
   }
@@ -68,6 +73,11 @@ void AnalyserHandler::Process(uint32_t frames_to_process) {
   // Analyser reflects the current input.
   analyser_.WriteInput(input_bus.get(), frames_to_process);
 
+  // Subsequent steps require `output_bus` to be valid.
+  if (!output_bus) {
+    return;
+  }
+
   if (!Input(0).IsConnected()) {
     // No inputs, so clear the output, and propagate the silence hint.
     output_bus->Zero();
diff --git a/blink/renderer/modules/webaudio/audio_worklet_node.cc b/blink/renderer/modules/webaudio/audio_worklet_node.cc
index 4538425395e8b7e25871c30fc6e217f545cc725b..9ae11ba5ceec761eaf8a0967964964647e88345e 100644
--- a/blink/renderer/modules/webaudio/audio_worklet_node.cc
+++ b/blink/renderer/modules/webaudio/audio_worklet_node.cc
@@ -105,12 +105,14 @@ void AudioWorkletHandler::Process(uint32_t frames_to_process) {
   // We also need to check if the global scope is valid before we request
   // the rendering in the AudioWorkletGlobalScope.
   if (processor_ && !processor_->hasErrorOccurred()) {
-    // If the input is not connected, inform the processor with nullptr.
+  // If the input or the output is not connected, inform the processor with
+  // nullptr.
     for (unsigned i = 0; i < NumberOfInputs(); ++i) {
       inputs_[i] = Input(i).IsConnected() ? Input(i).Bus() : nullptr;
     }
     for (unsigned i = 0; i < NumberOfOutputs(); ++i) {
-      outputs_[i] = WrapRefCounted(Output(i).Bus());
+    outputs_[i] = Output(i).RenderingFanOutCount() > 0
+        ? WrapRefCounted(Output(i).Bus()) : nullptr;
     }
 
     for (const auto& param_name : param_value_map_.Keys()) {
diff --git a/blink/renderer/modules/webaudio/audio_worklet_processor.cc b/blink/renderer/modules/webaudio/audio_worklet_processor.cc
index e366b21fbff7423e14c0d4346c6ccb254d5c6578..1f021d0f2d3cdf50a8eed4f55322d6ae927d11c1 100644
--- a/blink/renderer/modules/webaudio/audio_worklet_processor.cc
+++ b/blink/renderer/modules/webaudio/audio_worklet_processor.cc
@@ -356,6 +356,12 @@ void AudioWorkletProcessor::CopyArrayBuffersToPort(
 
   for (uint32_t bus_index = 0; bus_index < audio_port.size(); ++bus_index) {
     const scoped_refptr<AudioBus>& audio_bus = audio_port[bus_index];
+
+    // nullptr indicates the output bus is not connected. Do not proceed.
+    if (!audio_bus) {
+      break;
+    }
+
     for (uint32_t channel_index = 0;
          channel_index < audio_bus->NumberOfChannels(); ++channel_index) {
       auto backing_store = array_buffers[bus_index][channel_index]
diff --git a/blink/renderer/modules/webaudio/deferred_task_handler.cc b/blink/renderer/modules/webaudio/deferred_task_handler.cc
index 28107a546e550009999a3c168dd5b6d0db589eb7..ffa26c53a563d75c0eea89808e47402b7221c868 100644
--- a/blink/renderer/modules/webaudio/deferred_task_handler.cc
+++ b/blink/renderer/modules/webaudio/deferred_task_handler.cc
@@ -171,6 +171,16 @@ void DeferredTaskHandler::UpdateAutomaticPullNodes() {
     if (try_locker.Locked()) {
       CopyToVector(automatic_pull_handlers_,
                    rendering_automatic_pull_handlers_);
+
+      // In rare cases, it is possible for automatic pull nodes' output bus
+      // to become stale. Make sure update their rendering output counts.
+      // crbug.com/1505080.
+      for (auto& handler : rendering_automatic_pull_handlers_) {
+        for (unsigned i = 0; i < handler->NumberOfOutputs(); ++i) {
+          handler->Output(i).UpdateRenderingState();
+        }
+      }
+
       automatic_pull_handlers_need_updating_ = false;
     }
   }