small fix

src/features/mark/MarkBoardTrack.vue

@@ -111,12 +111,12 @@
             <div style="height: 32px">
               <transition-group name="score-number-animation" tag="span">
                 <span
-                  :key="store.currentTask.markResult.scoreList[index] || 0"
+                  :key="store.currentTask?.markResult.scoreList[index] || 0"
                   class="tw-font-medium tw-text-2xl score tw-inline-block"
                 >
                   <!-- 特殊的空格符号 -->
                   <!-- eslint-disable-next-line no-irregular-whitespace -->
-                  {{ store.currentTask.markResult.scoreList[index] ?? " " }}
+                  {{ store.currentTask?.markResult.scoreList[index] ?? " " }}
                 </span>
               </transition-group>
             </div>