fixed#6193

src/components/collapse/collapse.vue

@@ -42,13 +42,14 @@
         methods: {
             setActive () {
                 const activeKey = this.getActiveKey();
-
+                this.$nextTick(() => {
                     this.$children.forEach((child, index) => {
                         const name = child.name || index.toString();
 
                         child.isActive = activeKey.indexOf(name) > -1;
                         child.index = index;
                     });
+                });
             },
             getActiveKey () {
                 let activeKey = this.currentValue || [];