diff --git a/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts b/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts
index f636df3..2e00034 100644
--- a/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts
+++ b/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts
@@ -53,7 +53,7 @@
   account?: AccountInfo;
 
   @property({type: Boolean})
-  mutable?: boolean;
+  mutable = false;
 
   @property({type: Boolean})
   expanded = false;
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-action.ts b/polygerrit-ui/app/elements/checks/gr-checks-action.ts
index 87cab46..aed07e0 100644
--- a/polygerrit-ui/app/elements/checks/gr-checks-action.ts
+++ b/polygerrit-ui/app/elements/checks/gr-checks-action.ts
@@ -26,7 +26,7 @@
   action!: Action;
 
   @property()
-  eventTarget?: EventTarget;
+  eventTarget: HTMLElement | null = null;
 
   private checksService = appContext.checksService;
 
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts
index 2bb9de5..bbd1708 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts
@@ -470,6 +470,7 @@
 };
 
 export interface GrHovercardBehaviorInterface {
+  _target: HTMLElement | null;
   ready(): void;
   removeListeners(): void;
   debounceHide(): void;
diff --git a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
index 026ca4c..e01c5d3 100644
--- a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
+++ b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
@@ -39,6 +39,7 @@
 import {GrButton} from '../gr-button/gr-button';
 import {getVotingRangeOrDefault} from '../../../utils/label-util';
 import {appContext} from '../../../services/app-context';
+import {ParsedChangeInfo} from '../../../types/types';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -72,7 +73,7 @@
   label = '';
 
   @property({type: Object})
-  change?: ChangeInfo;
+  change?: ParsedChangeInfo;
 
   @property({type: Object})
   account?: AccountInfo;
diff --git a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_test.ts b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_test.ts
index b3235fa..b1bd6fa 100644
--- a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_test.ts
+++ b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info_test.ts
@@ -31,7 +31,7 @@
 import {GrAccountLink} from '../gr-account-link/gr-account-link';
 import {
   createAccountWithIdNameAndEmail,
-  createChange,
+  createParsedChange,
 } from '../../../test/test-data-generators';
 import {LabelInfo} from '../../../types/common';
 
@@ -46,7 +46,7 @@
 
     // Needed to trigger computed bindings.
     element.account = {};
-    element.change = {...createChange(), labels: {}};
+    element.change = {...createParsedChange(), labels: {}};
   });
 
   suite('remove reviewer votes', () => {
@@ -60,7 +60,7 @@
       sinon.stub(element, '_computeValueTooltip').returns('');
       element.account = account;
       element.change = {
-        ...createChange(),
+        ...createParsedChange(),
         labels: {'Code-Review': label},
       };
       element.labelInfo = label;