Fix variable name

themes/mantis/app/entity-groups/journal-entities/item-pages/journal-volume/journal-volume.component.html

@@ -4,7 +4,7 @@
 
             <div class="col-12 col-md-2 d-flex flex-md-column justify-content-between">
                 <ds-metadata-field-wrapper>
-                    <ds-thumbnail [thumbnail]="item.getThumbnail() | async"></ds-thumbnail>
+                    <ds-thumbnail [thumbnail]="object.getThumbnail() | async"></ds-thumbnail>
                 </ds-metadata-field-wrapper>
                 <div>
                     <a class="btn btn-secondary"