diff --git a/pageserver/src/tenant/timeline/detach_ancestor.rs b/pageserver/src/tenant/timeline/detach_ancestor.rs
index 1f52433e4e..1082ee37d1 100644
--- a/pageserver/src/tenant/timeline/detach_ancestor.rs
+++ b/pageserver/src/tenant/timeline/detach_ancestor.rs
@@ -1069,7 +1069,7 @@ pub(super) async fn detach_and_reparent(
         "to detach and reparent, gc must still be blocked"
     );
 
-    let (ancestor, ancestor_lsn) = match ancestor {
+    let (ancestor, ancestor_lsn, was_detached) = match ancestor {
         Ancestor::NotDetached(ancestor, ancestor_lsn) => {
             // this has to complete before any reparentings because otherwise they would not have
             // layers on the new parent.
@@ -1082,9 +1082,9 @@ pub(super) async fn detach_and_reparent(
                 .await
                 .context("publish layers and detach ancestor")?;
 
-            (ancestor, ancestor_lsn)
+            (ancestor, ancestor_lsn, true)
         }
-        Ancestor::Detached(ancestor, ancestor_lsn) => (ancestor, ancestor_lsn),
+        Ancestor::Detached(ancestor, ancestor_lsn) => (ancestor, ancestor_lsn, false),
     };
 
     let mut tasks = tokio::task::JoinSet::new();
@@ -1215,7 +1215,7 @@ pub(super) async fn detach_and_reparent(
         Ok(DetachingAndReparenting::Reparented(reparented))
     } else {
         Ok(DetachingAndReparenting::SomeReparentingFailed {
-            must_restart: reparented.is_empty(),
+            must_restart: !reparented.is_empty() || was_detached,
         })
     }
 }