diff --git a/src/main/java/de/tum/cit/aet/artemis/lecture/web/AttachmentUnitResource.java b/src/main/java/de/tum/cit/aet/artemis/lecture/web/AttachmentUnitResource.java
index 890e47898c6e..ac71195e08a1 100644
--- a/src/main/java/de/tum/cit/aet/artemis/lecture/web/AttachmentUnitResource.java
+++ b/src/main/java/de/tum/cit/aet/artemis/lecture/web/AttachmentUnitResource.java
@@ -115,18 +115,18 @@ public ResponseEntity<AttachmentUnit> getAttachmentUnit(@PathVariable Long attac
      * @param attachmentUnit   the attachment unit with updated content
      * @param attachment       the attachment with updated content
      * @param file             the optional file to upload
+     * @param hiddenPages      the pages to be hidden in the attachment unit
      * @param studentVersion   the student version of the file to upload
      * @param keepFilename     specifies if the original filename should be kept or not
      * @param notificationText the text to be used for the notification. No notification will be sent if the parameter is not set
-     * @param hiddenPages      the pages to be hidden in the attachment unit. No hidden pages will be sent if the parameter is not set
      * @return the ResponseEntity with status 200 (OK) and with body the updated attachmentUnit
      */
     @PutMapping(value = "lectures/{lectureId}/attachment-units/{attachmentUnitId}", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
     @EnforceAtLeastEditor
     public ResponseEntity<AttachmentUnit> updateAttachmentUnit(@PathVariable Long lectureId, @PathVariable Long attachmentUnitId, @RequestPart AttachmentUnit attachmentUnit,
             @RequestPart Attachment attachment, @RequestPart(required = false) MultipartFile file, @RequestPart(required = false) MultipartFile studentVersion,
-            @RequestParam(defaultValue = "false") boolean keepFilename, @RequestParam(value = "notificationText", required = false) String notificationText,
-            @RequestParam(value = "hiddenPages", required = false) String hiddenPages) {
+            @RequestPart(required = false) String hiddenPages, @RequestParam(defaultValue = "false") boolean keepFilename,
+            @RequestParam(value = "notificationText", required = false) String notificationText) {
         log.debug("REST request to update an attachment unit : {}", attachmentUnit);
         AttachmentUnit existingAttachmentUnit = attachmentUnitRepository.findWithSlidesAndCompetenciesByIdElseThrow(attachmentUnitId);
         checkAttachmentUnitCourseAndLecture(existingAttachmentUnit, lectureId);
diff --git a/src/main/webapp/app/lecture/lecture-unit/lecture-unit-management/attachmentUnit.service.ts b/src/main/webapp/app/lecture/lecture-unit/lecture-unit-management/attachmentUnit.service.ts
index b7e6dafd7c1a..4a5e3ed80a71 100644
--- a/src/main/webapp/app/lecture/lecture-unit/lecture-unit-management/attachmentUnit.service.ts
+++ b/src/main/webapp/app/lecture/lecture-unit/lecture-unit-management/attachmentUnit.service.ts
@@ -37,15 +37,14 @@ export class AttachmentUnitService {
             .pipe(map((res: EntityResponseType) => this.lectureUnitService.convertLectureUnitResponseDatesFromServer(res)));
     }
 
-    update(lectureId: number, attachmentUnitId: number, formData: FormData, notificationText?: string, hiddenPages?: string): Observable<EntityResponseType> {
+    update(lectureId: number, attachmentUnitId: number, formData: FormData, notificationText?: string): Observable<EntityResponseType> {
         /** Ngsw-worker is bypassed temporarily to fix Chromium file upload issue
          * See: https://issues.chromium.org/issues/374550348
          **/
         return this.httpClient
             .put<AttachmentUnit>(
                 `${this.resourceURL}/lectures/${lectureId}/attachment-units/${attachmentUnitId}?keepFilename=true` +
-                    (notificationText ? `&notificationText=${notificationText}` : '') +
-                    (hiddenPages ? `&hiddenPages=${hiddenPages}` : ''),
+                    (notificationText ? `&notificationText=${notificationText}` : ''),
                 formData,
                 { headers: { 'ngsw-bypass': 'true' }, observe: 'response' },
             )
diff --git a/src/main/webapp/app/lecture/pdf-preview/pdf-preview.component.ts b/src/main/webapp/app/lecture/pdf-preview/pdf-preview.component.ts
index 75e71c166801..a96ecc304f5e 100644
--- a/src/main/webapp/app/lecture/pdf-preview/pdf-preview.component.ts
+++ b/src/main/webapp/app/lecture/pdf-preview/pdf-preview.component.ts
@@ -180,30 +180,21 @@ export class PdfPreviewComponent implements OnInit, OnDestroy {
 
             const finalHiddenPages = this.getHiddenPages();
 
-            if (finalHiddenPages.length <= 0) {
-                this.attachmentUnitService.update(this.attachmentUnit()!.lecture!.id!, this.attachmentUnit()!.id!, formData).subscribe({
-                    next: () => {
-                        this.alertService.success('artemisApp.attachment.pdfPreview.attachmentUpdateSuccess');
-                        this.router.navigate(['course-management', this.course()?.id, 'lectures', this.attachmentUnit()!.lecture!.id, 'unit-management']);
-                    },
-                    error: (error) => {
-                        this.alertService.error('artemisApp.attachment.pdfPreview.attachmentUpdateError', { error: error.message });
-                    },
-                });
-            } else {
+            if (finalHiddenPages.length > 0) {
                 const pdfFileWithHiddenPages = await this.createStudentVersionOfAttachment(finalHiddenPages);
                 formData.append('studentVersion', pdfFileWithHiddenPages!);
-
-                this.attachmentUnitService.update(this.attachmentUnit()!.lecture!.id!, this.attachmentUnit()!.id!, formData, undefined, finalHiddenPages.join(',')).subscribe({
-                    next: () => {
-                        this.alertService.success('artemisApp.attachment.pdfPreview.attachmentUpdateSuccess');
-                        this.router.navigate(['course-management', this.course()?.id, 'lectures', this.attachmentUnit()!.lecture!.id, 'unit-management']);
-                    },
-                    error: (error) => {
-                        this.alertService.error('artemisApp.attachment.pdfPreview.attachmentUpdateError', { error: error.message });
-                    },
-                });
+                formData.append('hiddenPages', finalHiddenPages.join(','));
             }
+
+            this.attachmentUnitService.update(this.attachmentUnit()!.lecture!.id!, this.attachmentUnit()!.id!, formData).subscribe({
+                next: () => {
+                    this.alertService.success('artemisApp.attachment.pdfPreview.attachmentUpdateSuccess');
+                    this.router.navigate(['course-management', this.course()?.id, 'lectures', this.attachmentUnit()!.lecture!.id, 'unit-management']);
+                },
+                error: (error) => {
+                    this.alertService.error('artemisApp.attachment.pdfPreview.attachmentUpdateError', { error: error.message });
+                },
+            });
         }
     }