diff --git a/templates/repo/issue/view_content/sidebar.tmpl b/templates/repo/issue/view_content/sidebar.tmpl
index af648387d..41c7e022c 100644
--- a/templates/repo/issue/view_content/sidebar.tmpl
+++ b/templates/repo/issue/view_content/sidebar.tmpl
@@ -413,7 +413,7 @@
 					<div class="df sb ac">
 						<div class="due-date tooltip {{if .Issue.IsOverdue}}text red{{end}}" {{if .Issue.IsOverdue}}data-content="{{.locale.Tr "repo.issues.due_date_overdue"}}"{{end}}>
 							{{svg "octicon-calendar" 16 "mr-3"}}
-							<time data-format="date" datetime="{{.Issue.DeadlineUnix.FormatLong}}">{{.Issue.DeadlineUnix.FormatDate}}</time>
+							<time data-format="date" datetime="{{.Issue.DeadlineUnix.FormatDate}}">{{.Issue.DeadlineUnix.FormatDate}}</time>
 						</div>
 						<div>
 							{{if and .HasIssuesOrPullsWritePermission (not .Repository.IsArchived)}}