update

app/Http/Controllers/Mobile/CourseController.php

@@ -1087,7 +1087,32 @@ class CourseController extends CommonController
             ->orderBy('start_time', 'asc')
             ->get();
 
+        $list->each(function ($calendar) {
+            if (!empty($calendar->course)) {
+                $calendar->course->start_time = $this->formatDateTimeWithSeconds($calendar->course->start_time ?? null);
+                $calendar->course->end_time = $this->formatDateTimeWithSeconds($calendar->course->end_time ?? null);
+            }
+            if (!empty($calendar->courseContent)) {
+                $calendar->courseContent->each(function ($content) {
+                    $content->start_time = $this->formatDateTimeWithSeconds($content->start_time ?? null);
+                    $content->end_time = $this->formatDateTimeWithSeconds($content->end_time ?? null);
+                });
+            }
+        });
+
         return $this->success($list);
     }
 
+    private function formatDateTimeWithSeconds($value)
+    {
+        if (empty($value)) {
+            return $value;
+        }
+        $timestamp = strtotime($value);
+        if ($timestamp === false) {
+            return $value;
+        }
+        return date('Y-m-d H:i:s', $timestamp);
+    }
+
 }