diff --git a/services/nginx/app/classes/invoice_period_flag_service.php b/services/nginx/app/classes/invoice_period_flag_service.php
index 8d5b7e58..bb8e0a56 100644
--- a/services/nginx/app/classes/invoice_period_flag_service.php
+++ b/services/nginx/app/classes/invoice_period_flag_service.php
@@ -320,6 +320,16 @@ class invoice_period_flag_service
     }
 
     public function warmManualFlagsCache(): void
+    {
+        $flags = $this->fetchActiveManualFlagsFromDb();
+
+        try {
+            (new redis())->cache_invoice_period_manual_flags($flags);
+        } catch (Throwable) {
+        }
+    }
+
+    private function fetchActiveManualFlagsFromDb(): array
     {
         global $db;
 
@@ -337,10 +347,7 @@ class invoice_period_flag_service
             }
         }
 
-        try {
-            (new redis())->cache_invoice_period_manual_flags($flags);
-        } catch (Throwable) {
-        }
+        return $flags;
     }
 
     private function formatStoredFlag(array $row): array
@@ -388,15 +395,11 @@ class invoice_period_flag_service
         }
 
         if (!is_array($flags)) {
-            // Cache miss — warm on demand and re-fetch
-            $this->warmManualFlagsCache();
+            // Cache miss — read from the database and refresh Redis without hiding active flags.
+            $flags = $this->fetchActiveManualFlagsFromDb();
             try {
-                $flags = (new redis())->get_invoice_period_manual_flags();
+                (new redis())->cache_invoice_period_manual_flags($flags);
             } catch (Throwable) {
-                return [];
-            }
-            if (!is_array($flags)) {
-                return [];
             }
         }
 
@@ -529,7 +532,7 @@ class invoice_period_flag_service
         }
 
         if (!is_array($flags)) {
-            $flags = $this->buildAutomaticFlagsForPeriod($dateFrom, $dateTo);
+            $flags = $this->calculateAutomaticFlagsForPeriod($dateFrom, $dateTo);
             $this->cacheAutomaticFlagsForPeriod($dateFrom, $dateTo, $flags);
         }
 
@@ -545,15 +548,17 @@ class invoice_period_flag_service
 
     public function warmAutomaticFlagsForPeriod(string $dateFrom, string $dateTo): void
     {
+        [$dateFrom, $dateTo] = $this->normalizePeriodDateRange($dateFrom, $dateTo);
         $this->cacheAutomaticFlagsForPeriod(
             $dateFrom,
             $dateTo,
-            $this->buildAutomaticFlagsForPeriod($dateFrom, $dateTo)
+            $this->calculateAutomaticFlagsForPeriod($dateFrom, $dateTo)
         );
     }
 
-    private function buildAutomaticFlagsForPeriod(string $dateFrom, string $dateTo): array
+    private function calculateAutomaticFlagsForPeriod(string $dateFrom, string $dateTo): array
     {
+        [$dateFrom, $dateTo] = $this->normalizePeriodDateRange($dateFrom, $dateTo);
         $rows = $this->getPeriodOrderItemRows($dateFrom, $dateTo, null);
         $attributes = $this->getCustomerAttributes(null);
 
@@ -611,6 +616,7 @@ class invoice_period_flag_service
 
     private function getPeriodOrderItemRows(string $dateFrom, string $dateTo, ?array $onlyCustomerNumbers): array
     {
+        [$dateFrom, $dateTo] = $this->normalizePeriodDateRange($dateFrom, $dateTo);
         try {
             $rows = (new redis())->get_invoice_period_order_item_rows($dateFrom, $dateTo);
         } catch (Throwable) {
@@ -639,6 +645,7 @@ class invoice_period_flag_service
 
     public function warmOrderItemRowsForPeriod(string $dateFrom, string $dateTo): void
     {
+        [$dateFrom, $dateTo] = $this->normalizePeriodDateRange($dateFrom, $dateTo);
         $rows = $this->fetchOrderItemRowsFromDb($dateFrom, $dateTo);
         try {
             (new redis())->cache_invoice_period_order_item_rows($dateFrom, $dateTo, $rows);
@@ -646,6 +653,24 @@ class invoice_period_flag_service
         }
     }
 
+    private function normalizePeriodDateRange(string $dateFrom, string $dateTo): array
+    {
+        return [
+            $this->normalizePeriodDate($dateFrom, true),
+            $this->normalizePeriodDate($dateTo, false),
+        ];
+    }
+
+    private function normalizePeriodDate(string $date, bool $startOfDay): string
+    {
+        $timestamp = strtotime($date);
+        if ($timestamp === false) {
+            return $date;
+        }
+
+        return date($startOfDay ? 'Y-m-d 00:00:00' : 'Y-m-d 23:59:59', $timestamp);
+    }
+
     private function fetchOrderItemRowsFromDb(string $dateFrom, string $dateTo): array
     {
         global $db;
diff --git a/services/nginx/app/classes/redis.php b/services/nginx/app/classes/redis.php
index 76c0c96a..709d88b1 100644
--- a/services/nginx/app/classes/redis.php
+++ b/services/nginx/app/classes/redis.php
@@ -392,7 +392,19 @@ class redis implements redis_i
 
     private function invoicePeriodCacheKey(string $prefix, string $dateFrom, string $dateTo): string
     {
-        return $prefix . ':' . $dateFrom . ':' . $dateTo;
+        return $prefix . ':'
+            . $this->normalizeInvoicePeriodCacheDate($dateFrom, true) . ':'
+            . $this->normalizeInvoicePeriodCacheDate($dateTo, false);
+    }
+
+    private function normalizeInvoicePeriodCacheDate(string $date, bool $startOfDay): string
+    {
+        $timestamp = strtotime($date);
+        if ($timestamp === false) {
+            return $date;
+        }
+
+        return date($startOfDay ? 'Y-m-d 00:00:00' : 'Y-m-d 23:59:59', $timestamp);
     }
 
     private function workfeedEmployeeNameCacheKey(string $employeeId): string
@@ -512,7 +524,11 @@ class redis implements redis_i
      */
     public function enqueue_invoice_period_warming(string $dateFrom, string $dateTo): self
     {
-        $this->get_client()->sadd('invoice_period_warming_queue', [$dateFrom . '|' . $dateTo]);
+        $this->get_client()->sadd('invoice_period_warming_queue', [
+            $this->normalizeInvoicePeriodCacheDate($dateFrom, true)
+                . '|'
+                . $this->normalizeInvoicePeriodCacheDate($dateTo, false),
+        ]);
         return $this;
     }
 
diff --git a/services/nginx/app/tests/Unit/Invoicing/InvoicePeriodFlagServiceTest.php b/services/nginx/app/tests/Unit/Invoicing/InvoicePeriodFlagServiceTest.php
index 4afefd5c..5c4330c9 100644
--- a/services/nginx/app/tests/Unit/Invoicing/InvoicePeriodFlagServiceTest.php
+++ b/services/nginx/app/tests/Unit/Invoicing/InvoicePeriodFlagServiceTest.php
@@ -21,6 +21,31 @@ function invoice_period_flag_service_invoke(string $method, array $args = []): m
     return $target->invokeArgs($service, $args);
 }
 
+it('normalizes invoice period date ranges to full-day timestamps before cache-backed reads', function (): void {
+    expect(invoice_period_flag_service_invoke('normalizePeriodDateRange', ['2025-03-01', '2025-03-31']))
+        ->toBe(['2025-03-01 00:00:00', '2025-03-31 23:59:59']);
+
+    expect(invoice_period_flag_service_invoke('normalizePeriodDateRange', [
+        '2025-03-01 00:00:00',
+        '2025-03-31 23:59:59',
+    ]))->toBe(['2025-03-01 00:00:00', '2025-03-31 23:59:59']);
+});
+
+it('canonicalizes invoice period redis keys for bare dates and normalized API timestamps', function (): void {
+    $reflection = new ReflectionClass(\classes\redis::class);
+    $redis = $reflection->newInstanceWithoutConstructor();
+    $key = $reflection->getMethod('invoicePeriodCacheKey');
+    $key->setAccessible(true);
+
+    expect($key->invoke($redis, 'invoice_period_automatic_flags', '2025-03-01', '2025-03-31'))
+        ->toBe($key->invoke(
+            $redis,
+            'invoice_period_automatic_flags',
+            '2025-03-01 00:00:00',
+            '2025-03-31 23:59:59'
+        ));
+});
+
 it('builds deterministic automatic flag fingerprints and interactive price message parts', function (): void {
     $row = [
         'customer_number' => 424242,