using DidMount instead of DidUpdate

cvat-ui/src/components/projects-page/project-list.tsx

@@ -42,7 +42,7 @@ export default function ProjectListComponent(): JSX.Element {
                 <Col className='cvat-projects-list' md={22} lg={18} xl={16} xxl={14}>
                     {projectInstances.map(
                         (row: any[]): JSX.Element => (
-                            <Row gutter={[8, 8]}>
+                            <Row key={row[0].id} gutter={[8, 8]}>
                                 {row.map((instance: any) => (
                                     <Col span={6} key={instance.id}>
                                         <ProjectItem projectInstance={instance} />

cvat-ui/src/components/task-page/task-page.tsx

@@ -28,14 +28,16 @@ interface TaskPageComponentProps {
 type Props = TaskPageComponentProps & RouteComponentProps<{ id: string }>;
 
 class TaskPageComponent extends React.PureComponent<Props> {
-    public componentDidUpdate(): void {
-        const {
-            deleteActivity, history, task, fetching, getTask,
-        } = this.props;
+    public componentDidMount(): void {
+        const { task, fetching, getTask } = this.props;
 
         if (task === null && !fetching) {
             getTask();
         }
+    }
+
+    public componentDidUpdate(): void {
+        const { deleteActivity, history } = this.props;
 
         if (deleteActivity) {
             history.replace('/tasks');