Fix setting of cancellation status

aleksis/apps/chronos/frontend/components/substitutions/SubstitutionCard.vue

@@ -74,13 +74,13 @@ import createOrPatchMixin from "aleksis.core/mixins/createOrPatchMixin.js";
         mandatory
         :disabled="loading"
         class="justify-self-end"
+        @change="changeCancel"
       >
         <v-chip
           filter
           outlined
           color="success"
           :value="false"
-          @click="changeCancel"
         >
           {{ $t("chronos.substitutions.overview.cancel.not_cancelled") }}
         </v-chip>
@@ -89,7 +89,6 @@ import createOrPatchMixin from "aleksis.core/mixins/createOrPatchMixin.js";
           outlined
           color="error"
           :value="true"
-          @click="changeCancel"
         >
           {{ $t("chronos.substitutions.overview.cancel.cancelled") }}
         </v-chip>
@@ -109,6 +108,7 @@ export default {
       loading: false,
       teachers: [],
       cancelled: undefined,
+      ready: false,
     };
   },
   props: {
@@ -141,12 +141,14 @@ export default {
       ]);
     },
     changeCancel() {
-      this.createOrPatch([
-        {
-          id: this.substitution.id,
-          cancelled: this.cancelled,
-        },
-      ]);
+      if (this.ready) {
+        this.createOrPatch([
+          {
+            id: this.substitution.id,
+            cancelled: this.cancelled,
+          },
+        ]);
+      }
     },
   },
   computed: {
@@ -179,6 +181,7 @@ export default {
   mounted() {
     this.teachers = this.substitution.teachers.map((teacher) => teacher.id);
     this.cancelled = this.substitution.cancelled;
+    this.ready = true;
   },
 };
 </script>