diff --git a/enterprise/app/services/whatsapp/incoming_call_service.rb b/enterprise/app/services/whatsapp/incoming_call_service.rb
index 3977578d0..c5621950f 100644
--- a/enterprise/app/services/whatsapp/incoming_call_service.rb
+++ b/enterprise/app/services/whatsapp/incoming_call_service.rb
@@ -35,13 +35,18 @@ class Whatsapp::IncomingCallService
     end
   end
 
+  # with_lock + reload here serializes against Whatsapp::CallService (agent
+  # actions hold call.with_lock across the Meta API call), so a webhook racing
+  # with a terminate can't overwrite a freshly-finalized terminal status.
   def mark_outbound_accepted(call, payload)
-    return unless call.outgoing?
-    return if call.in_progress? || call.terminal?
+    call.with_lock do
+      next unless call.outgoing?
+      next if call.in_progress? || call.terminal?
 
-    started_at = Time.zone.at(payload[:timestamp].to_i) if payload[:timestamp].present?
-    update_call!(call, 'in_progress', started_at: started_at || Time.current)
-    broadcast(call, 'voice_call.outbound_accepted')
+      started_at = Time.zone.at(payload[:timestamp].to_i) if payload[:timestamp].present?
+      update_call!(call, 'in_progress', started_at: started_at || Time.current)
+      broadcast(call, 'voice_call.outbound_accepted')
+    end
   end
 
   def handle_connect(payload)
@@ -81,42 +86,40 @@ class Whatsapp::IncomingCallService
   # Meta's SDP answer so the handshake completes during ringing; the call
   # stays in `ringing` until status=ACCEPTED arrives.
   def accept_outbound_call(call, payload)
-    return if call.in_progress? || call.terminal?
+    call.with_lock do
+      next if call.in_progress? || call.terminal?
 
-    # Pin setup:active so browsers don't renegotiate when Meta echoes actpass.
-    sdp_answer = payload.dig(:session, :sdp)&.gsub('a=setup:actpass', 'a=setup:active')
-    call.update!(meta: (call.meta || {}).merge('sdp_answer' => sdp_answer))
-    broadcast(call, 'voice_call.outbound_connected', sdp_answer: sdp_answer)
+      # Pin setup:active so browsers don't renegotiate when Meta echoes actpass.
+      sdp_answer = payload.dig(:session, :sdp)&.gsub('a=setup:actpass', 'a=setup:active')
+      call.update!(meta: (call.meta || {}).merge('sdp_answer' => sdp_answer))
+      broadcast(call, 'voice_call.outbound_connected', sdp_answer: sdp_answer)
+    end
   end
 
   def handle_terminate(payload)
-    # Webhooks can arrive out of order (terminate before connect under tunnel/network
-    # delays). Materialise a missed-call record so the contact's "called and hung up"
-    # still surfaces in the dashboard instead of being silently dropped.
-    call = Call.whatsapp.find_by(provider_call_id: payload[:id]) || build_missed_inbound_call(payload)
-    return unless call
-    # Webhook retries can re-deliver terminate after we've already finalized the
-    # call; don't recompute status or a duration=0 retry can flip a completed
-    # short call back to no_answer.
-    return if call.terminal?
+    call = Call.whatsapp.find_by(provider_call_id: payload[:id])
+    if call.nil?
+      # No row yet means either an out-of-order terminate (rare in practice — Meta
+      # delivery is FIFO) or, more dangerously, an outbound terminate landing in
+      # the window between the controller's Meta API call and Call.create!.
+      # Materialising as inbound here would collide with the unique
+      # (provider, provider_call_id) index. Skip; controller commits seal it.
+      Rails.logger.warn "[WHATSAPP CALL] Terminate for unknown call #{payload[:id]}; skipping"
+      return
+    end
 
-    duration = payload[:duration]&.to_i
-    status = answered?(call, duration) ? 'completed' : 'no_answer'
-    meta = (call.meta || {}).merge('ended_at' => Time.zone.now.to_i)
-    update_call!(call, status, duration_seconds: duration, end_reason: payload[:terminate_reason], meta: meta)
-    broadcast(call, 'voice_call.ended', status: call.display_status, duration_seconds: call.duration_seconds)
-  end
+    call.with_lock do
+      # Webhook retries can re-deliver terminate after we've already finalized the
+      # call; don't recompute status or a duration=0 retry can flip a completed
+      # short call back to no_answer.
+      next if call.terminal?
 
-  # No connect was ever processed (webhook reordering or never delivered) — build a
-  # bare Call+Message for the contact so the UI shows the missed-call bubble.
-  def build_missed_inbound_call(payload)
-    Voice::InboundCallBuilder.perform!(
-      inbox: inbox, from_number: "+#{payload[:from]}", call_sid: payload[:id],
-      provider: :whatsapp,
-      extra_meta: { 'ice_servers' => Call.default_ice_servers }
-    )
-  rescue ActiveRecord::RecordNotUnique
-    Call.whatsapp.find_by(provider_call_id: payload[:id])
+      duration = payload[:duration]&.to_i
+      status = answered?(call, duration) ? 'completed' : 'no_answer'
+      meta = (call.meta || {}).merge('ended_at' => Time.zone.now.to_i)
+      update_call!(call, status, duration_seconds: duration, end_reason: payload[:terminate_reason], meta: meta)
+      broadcast(call, 'voice_call.ended', status: call.display_status, duration_seconds: call.duration_seconds)
+    end
   end
 
   # accepted_by_agent_id is the initiating agent on outbound calls, so it only signals "answered" for inbound.
diff --git a/spec/enterprise/services/whatsapp/incoming_call_service_spec.rb b/spec/enterprise/services/whatsapp/incoming_call_service_spec.rb
index caf69d74c..5dacff6f2 100644
--- a/spec/enterprise/services/whatsapp/incoming_call_service_spec.rb
+++ b/spec/enterprise/services/whatsapp/incoming_call_service_spec.rb
@@ -114,6 +114,21 @@ describe Whatsapp::IncomingCallService do
     end
   end
 
+  describe 'terminate with no local row yet' do
+    it 'logs and skips instead of materialising an inbound missed-call row' do
+      allow(inbox.channel).to receive(:voice_enabled?).and_return(true)
+      allow(Rails.logger).to receive(:warn)
+      allow(ActionCable.server).to receive(:broadcast)
+
+      params = call_payload(event: 'terminate', duration: 0, terminate_reason: 'no_answer')
+
+      expect { described_class.new(inbox: inbox, params: params).perform }
+        .not_to change(Call, :count)
+      expect(Rails.logger).to have_received(:warn).with(/Terminate for unknown call/)
+      expect(ActionCable.server).not_to have_received(:broadcast)
+    end
+  end
+
   describe 'outbound connect with no local row yet' do
     it 'does not mint an inbound call when sdp_type is answer' do
       allow(inbox.channel).to receive(:voice_enabled?).and_return(true)