diff --git a/src/addon/mod/assign/components/submission/addon-mod-assign-submission.html b/src/addon/mod/assign/components/submission/addon-mod-assign-submission.html
index ea03450af..84e54a560 100644
--- a/src/addon/mod/assign/components/submission/addon-mod-assign-submission.html
+++ b/src/addon/mod/assign/components/submission/addon-mod-assign-submission.html
@@ -215,6 +215,12 @@
                     <p *ngIf="feedback.gradeddate">{{ feedback.gradeddate * 1000 | coreFormatDate }}</p>
                 </a>
 
+                <!-- Grader is hidden, display only the grade date. -->
+                <ion-item text-wrap *ngIf="!grader && feedback.gradeddate">
+                    <h2>{{ 'addon.mod_assign.gradedon' | translate }}</h2>
+                    <p>{{ feedback.gradeddate * 1000 | coreFormatDate }}</p>
+                </ion-item>
+
                 <!-- Warning message if cannot save grades. -->
                 <div *ngIf="isGrading && !canSaveGrades" class="core-warning-card" icon-start>
                     <ion-icon name="warning"></ion-icon>
diff --git a/src/addon/mod/assign/components/submission/submission.ts b/src/addon/mod/assign/components/submission/submission.ts
index cffefe88d..5b65ab853 100644
--- a/src/addon/mod/assign/components/submission/submission.ts
+++ b/src/addon/mod/assign/components/submission/submission.ts
@@ -485,12 +485,14 @@ export class AddonModAssignSubmissionComponent implements OnInit, OnDestroy {
             this.feedback = feedback;
 
             // If we have data about the grader, get its profile.
-            if (feedback.grade && feedback.grade.grader) {
+            if (feedback.grade && feedback.grade.grader > 0) {
                 this.userProvider.getProfile(feedback.grade.grader, this.courseId).then((profile) => {
                     this.grader = profile;
                 }).catch(() => {
                     // Ignore errors.
                 });
+            } else {
+                delete this.grader;
             }
 
             // Check if the grade uses advanced grading.
diff --git a/src/addon/mod/assign/providers/prefetch-handler.ts b/src/addon/mod/assign/providers/prefetch-handler.ts
index 93ecb3f68..7505ee97b 100644
--- a/src/addon/mod/assign/providers/prefetch-handler.ts
+++ b/src/addon/mod/assign/providers/prefetch-handler.ts
@@ -392,7 +392,7 @@ export class AddonModAssignPrefetchHandler extends CoreCourseActivityPrefetchHan
         // Prefetch feedback.
         if (submission.feedback) {
             // Get profile and image of the grader.
-            if (submission.feedback.grade && submission.feedback.grade.grader && submission.feedback.grade.grader != -1) {
+            if (submission.feedback.grade && submission.feedback.grade.grader > 0) {
                 userIds.push(submission.feedback.grade.grader);
             }