diff --git a/apps/admin/src/pages/Classes/detail.tsx b/apps/admin/src/pages/Classes/detail.tsx
index fef152e6..52a6d35a 100644
--- a/apps/admin/src/pages/Classes/detail.tsx
+++ b/apps/admin/src/pages/Classes/detail.tsx
@@ -176,11 +176,16 @@ const ClassDetailPage: React.FC = () => {
     }
     setAddingTeacher(true);
     try {
-      await api.post(`/classes/${id}/teachers`, {
+      const result = await api.post<ClassTeacher[]>(`/classes/${id}/teachers`, {
         userId: teacherUserId,
         roleType: teacherRole,
         subjects: teacherSubjects,
       });
+      // 后端对全部科目已存在的情况返回空数组（不写审计/通知），前端如实提示避免误以为有新增
+      if (result.length === 0) {
+        message.warning('该教师已分配相同科目，未新增');
+        return;
+      }
       setTeacherModalOpen(false);
       fetchDetail();
       message.success('已添加');
diff --git a/apps/admin/src/pages/Schedules/ScheduleModals.tsx b/apps/admin/src/pages/Schedules/ScheduleModals.tsx
index f5d2a972..6b50136d 100644
--- a/apps/admin/src/pages/Schedules/ScheduleModals.tsx
+++ b/apps/admin/src/pages/Schedules/ScheduleModals.tsx
@@ -185,6 +185,12 @@ export const ScheduleModal: React.FC<ScheduleModalProps> = ({
     >
       {mode !== 'detail' ? (
         <Form form={form} layout="vertical" scrollToFirstError style={{ marginTop: 16 }}>
+          {/* teacherId 由父组件 handleTeacherChange 通过 setFieldValue 写入（下拉为复合 key 受控组件，
+              不直接绑 name）；用隐藏字段注册，保证 validateFields 返回、resetFields 清理（否则
+              提交丢失 teacherId，且新开创建弹窗残留上次编辑的老师） */}
+          <Form.Item name="teacherId" hidden>
+            <Input />
+          </Form.Item>
           <Form.Item name="classId" label="班级" rules={[{ required: true, message: '请选择班级' }]}>
             <Select
               placeholder="选择班级"
diff --git a/apps/admin/src/pages/Schedules/index.tsx b/apps/admin/src/pages/Schedules/index.tsx
index f9c5766b..2c4e631a 100644
--- a/apps/admin/src/pages/Schedules/index.tsx
+++ b/apps/admin/src/pages/Schedules/index.tsx
@@ -282,8 +282,10 @@ const SchedulesPage: React.FC = () => {
       setSelectedSchedules([]);
       setEditingSchedule(null);
       setModalMode('create');
-      // 作废编辑/默认值流程中在途的教师请求，避免过期响应回填刚重置的表单
+      // 作废编辑/默认值流程中在途的教师请求，避免过期响应回填刚重置的表单；
+      // 本路径不发新请求，同时复位 loading，防止过期响应因 seq 不匹配而不清 loading 导致永久 spinner
       teacherReqSeq.current += 1;
+      setClassTeachersLoading(false);
       form.resetFields();
       form.setFieldsValue({ classroomId, weekDay, attendanceAdvanceMinutes: 30 });
       setModalOpen(true);
@@ -674,6 +676,7 @@ const SchedulesPage: React.FC = () => {
           setEditingSchedule(null);
           setModalMode('create');
           teacherReqSeq.current += 1; // 作废在途教师请求，防止过期响应污染新建表单
+          setClassTeachersLoading(false);
           form.resetFields();
           form.setFieldsValue({
             classroomId: selectedCell?.classroomId,
diff --git a/apps/admin/src/pages/Schedules/schedule-conflicts.ts b/apps/admin/src/pages/Schedules/schedule-conflicts.ts
index 432acaba..0091e3f3 100644
--- a/apps/admin/src/pages/Schedules/schedule-conflicts.ts
+++ b/apps/admin/src/pages/Schedules/schedule-conflicts.ts
@@ -57,7 +57,8 @@ export function findTimeConflicts(
   if (!newStartDate || !newEndDate) return [];
   return (weekMatrix[classroomId]?.[weekDay] || []).filter((schedule) => {
     if (schedule.id !== undefined && schedule.id !== null && schedule.id === editingId) return false;
-    if (schedule.status === 'inactive') return false;
+    // 与后端 checkConflict 语义一致：仅 active 排课参与冲突（后端还有 cancelled 等状态）
+    if (schedule.status !== 'active') return false;
     // 前面已保证 newStartDate/newEndDate 均存在（缺失直接返回空）
     if (!dateRangesOverlap(schedule, newStartDate, newEndDate)) return false;
     const existingStart = toMinutes(schedule.startTime);