diff --git a/src/addons/calendar/components/calendar/calendar.ts b/src/addons/calendar/components/calendar/calendar.ts
index 1e8bf8d73..aef2a3a74 100644
--- a/src/addons/calendar/components/calendar/calendar.ts
+++ b/src/addons/calendar/components/calendar/calendar.ts
@@ -340,7 +340,9 @@ export class AddonCalendarCalendarComponent implements OnInit, DoCheck, OnDestro
     ngOnDestroy(): void {
         this.undeleteEventObserver?.off();
         this.manager?.destroy();
-        this.managerUnsubscribe && this.managerUnsubscribe();
+        this.managerUnsubscribe?.();
+
+        delete this.manager;
     }
 
 }
diff --git a/src/addons/calendar/pages/day/day.page.ts b/src/addons/calendar/pages/day/day.page.ts
index 839a3a7d5..3c266ee85 100644
--- a/src/addons/calendar/pages/day/day.page.ts
+++ b/src/addons/calendar/pages/day/day.page.ts
@@ -457,7 +457,9 @@ export class AddonCalendarDayPage implements OnInit, OnDestroy {
         this.filterChangedObserver?.off();
         this.manager?.getSource().forgetRelatedSources();
         this.manager?.destroy();
-        this.managerUnsubscribe && this.managerUnsubscribe();
+        this.managerUnsubscribe?.();
+
+        delete this.manager;
     }
 
 }
diff --git a/src/addons/mod/book/pages/contents/contents.ts b/src/addons/mod/book/pages/contents/contents.ts
index fef0d3775..9c290473e 100644
--- a/src/addons/mod/book/pages/contents/contents.ts
+++ b/src/addons/mod/book/pages/contents/contents.ts
@@ -314,8 +314,10 @@ export class AddonModBookContentsPage implements OnInit, OnDestroy {
      * @inheritdoc
      */
     ngOnDestroy(): void {
-        this.managerUnsubscribe && this.managerUnsubscribe();
         this.manager?.destroy();
+        this.managerUnsubscribe?.();
+
+        delete this.manager;
     }
 
 }
diff --git a/src/core/services/tests/utils/dom.test.ts b/src/core/services/tests/utils/dom.test.ts
index 3be772386..45e8499d9 100644
--- a/src/core/services/tests/utils/dom.test.ts
+++ b/src/core/services/tests/utils/dom.test.ts
@@ -18,6 +18,7 @@ import { AlertController, Translate } from '@singletons';
 import { mock, mockSingleton, mockTranslate } from '@/testing/utils';
 import { CoreSiteError } from '@classes/errors/siteerror';
 import { CoreSites } from '@services/sites';
+import { OverlayEventDetail } from '@ionic/core';
 
 describe('CoreDomUtilsProvider', () => {
 
@@ -56,4 +57,30 @@ describe('CoreDomUtilsProvider', () => {
         });
     });
 
+    it('ignores alert inputs on cancel', async () => {
+        // Arrange.
+        const mockAlert = mock<HTMLIonAlertElement>({
+            present: () => Promise.resolve(),
+            onWillDismiss: () => Promise.resolve({
+                data: {
+                    values: {
+                        'textarea-prompt': 'Not empty!',
+                    },
+                },
+                role: 'cancel',
+            } as OverlayEventDetail<any>), // eslint-disable-line @typescript-eslint/no-explicit-any
+        });
+
+        mockSingleton(AlertController, mock({ create: () => Promise.resolve(mockAlert) }));
+
+        // Act.
+        const result = await domUtils.showTextareaPrompt('Age', 'How old are you?', [
+            { text: 'Cancel', role: 'cancel' },
+            { text: 'Save' },
+        ]);
+
+        // Assert.
+        expect(result).toBeUndefined();
+    });
+
 });
diff --git a/src/core/services/utils/dom.ts b/src/core/services/utils/dom.ts
index 581880eeb..865a2501b 100644
--- a/src/core/services/utils/dom.ts
+++ b/src/core/services/utils/dom.ts
@@ -1659,6 +1659,10 @@ export class CoreDomUtilsProvider {
 
         const result = await alert.onWillDismiss();
 
+        if (result.role === 'cancel') {
+            return;
+        }
+
         return result.data?.values?.['textarea-prompt'];
     }