diff --git a/app/Models/Invoice.php b/app/Models/Invoice.php
index a6bfd225..cc207c46 100644
--- a/app/Models/Invoice.php
+++ b/app/Models/Invoice.php
@@ -364,6 +364,10 @@ public function hasSignificantUnderpayment(): bool
             return false;
         }
 
+        if (!$this->hasPaymentActivity()) {
+            return false;
+        }
+
         $confirmedUsd = $this->sumPaymentsUsd(true);
         if ($confirmedUsd + self::UNDERPAY_USD_TOLERANCE >= $expectedUsd) {
             return false;
@@ -398,6 +402,10 @@ public function underpaymentPercent(): ?float
             return null;
         }
 
+        if (!$this->hasPaymentActivity()) {
+            return null;
+        }
+
         $confirmedUsd = $this->sumPaymentsUsd(true);
         if ($confirmedUsd + self::UNDERPAY_USD_TOLERANCE >= $expectedUsd) {
             return null;
@@ -763,6 +771,17 @@ private function paymentIsConfirmed(InvoicePayment $payment): bool
         return $payment->is_adjustment || $payment->confirmed_at !== null;
     }
 
+    private function hasPaymentActivity(): bool
+    {
+        if ($this->relationLoaded('payments')) {
+            return $this->activePayments()->isNotEmpty();
+        }
+
+        return $this->payments()
+            ->whereNull('ignored_at')
+            ->exists();
+    }
+
     private function activePayments(): Collection
     {
         $payments = $this->relationLoaded('payments')
diff --git a/tests/Unit/InvoicePaymentSummaryTest.php b/tests/Unit/InvoicePaymentSummaryTest.php
index 8a666d23..29f3278d 100644
--- a/tests/Unit/InvoicePaymentSummaryTest.php
+++ b/tests/Unit/InvoicePaymentSummaryTest.php
@@ -180,4 +180,74 @@ public function test_reattributed_payments_count_only_on_the_destination_invoice
         $this->assertSame(0, $destinationSummary['outstanding_sats']);
         $this->assertSame(0.0, $destinationSummary['outstanding_usd']);
     }
+
+    public function test_fresh_invoice_without_payment_activity_is_not_flagged_as_underpaid(): void
+    {
+        $user = User::factory()->create();
+        $client = Client::create([
+            'user_id' => $user->id,
+            'name' => 'Acme',
+            'email' => 'billing@acme.test',
+        ]);
+
+        $invoice = Invoice::create([
+            'user_id' => $user->id,
+            'client_id' => $client->id,
+            'number' => 'INV-3001',
+            'amount_usd' => 100,
+            'btc_rate' => 50_000,
+            'amount_btc' => 0.002,
+            'payment_address' => 'tb1qfreshinvoice',
+            'status' => 'sent',
+            'invoice_date' => now()->toDateString(),
+        ]);
+
+        $summary = $invoice->paymentSummary(['rate_usd' => 50_000]);
+
+        $this->assertFalse($invoice->hasSignificantUnderpayment());
+        $this->assertNull($invoice->underpaymentPercent());
+        $this->assertFalse($invoice->requiresClientUnderpayAlert());
+        $this->assertSame(0.0, $summary['confirmed_usd']);
+        $this->assertSame(100.0, $summary['outstanding_usd']);
+    }
+
+    public function test_partial_payment_activity_is_still_flagged_as_underpaid(): void
+    {
+        $user = User::factory()->create();
+        $client = Client::create([
+            'user_id' => $user->id,
+            'name' => 'Acme',
+            'email' => 'billing@acme.test',
+        ]);
+
+        $invoice = Invoice::create([
+            'user_id' => $user->id,
+            'client_id' => $client->id,
+            'number' => 'INV-3002',
+            'amount_usd' => 100,
+            'btc_rate' => 50_000,
+            'amount_btc' => 0.002,
+            'payment_address' => 'tb1qpartialinvoice',
+            'status' => 'sent',
+            'invoice_date' => now()->toDateString(),
+        ]);
+
+        InvoicePayment::create([
+            'invoice_id' => $invoice->id,
+            'txid' => 'tx-partial-underpay',
+            'sats_received' => 40_000,
+            'detected_at' => now(),
+            'confirmed_at' => now(),
+            'usd_rate' => 50_000,
+            'fiat_amount' => 20.00,
+        ]);
+
+        $summary = $invoice->fresh()->paymentSummary(['rate_usd' => 50_000]);
+
+        $this->assertTrue($invoice->fresh()->hasSignificantUnderpayment());
+        $this->assertSame(80.0, round($invoice->fresh()->underpaymentPercent(), 1));
+        $this->assertTrue($invoice->fresh()->requiresClientUnderpayAlert());
+        $this->assertSame(20.0, $summary['confirmed_usd']);
+        $this->assertSame(80.0, $summary['outstanding_usd']);
+    }
 }