diff --git a/infra/api/src/index.ts b/infra/api/src/index.ts
index 9b31fe3..37d4679 100644
--- a/infra/api/src/index.ts
+++ b/infra/api/src/index.ts
@@ -673,7 +673,7 @@ async function fanInExistingPosts(readerDid: string, authorDid: string, publicat
     const postRkey = (post.SK as string).slice('p#'.length);
     const item: Record<string, unknown> = {
       PK: `u#${readerDid}#timeline`,
-      SK: `${new Date(Math.min(new Date(post.publishedAt as string).getTime(), Date.now())).toISOString()}#${postRkey}`,
+      SK: `${(post.GSI1SK as string | undefined)?.split('#')[0] ?? new Date(Math.min(new Date(post.publishedAt as string).getTime(), Date.now())).toISOString()}#${postRkey}`,
       entityType: 'timeline-item',
       authorDid,
       rkey: postRkey,
diff --git a/infra/backfill/src/index.ts b/infra/backfill/src/index.ts
index 9124716..6b3c119 100644
--- a/infra/backfill/src/index.ts
+++ b/infra/backfill/src/index.ts
@@ -231,7 +231,7 @@ async function fanInExistingPosts(
     const postRkey = (post.SK as string).slice('p#'.length)
     const item: Record<string, unknown> = {
       PK: `u#${readerDid}#timeline`,
-      SK: `${new Date(Math.min(new Date(post.publishedAt as string).getTime(), Date.now())).toISOString()}#${postRkey}`,
+      SK: `${(post.GSI1SK as string | undefined)?.split('#')[0] ?? new Date(Math.min(new Date(post.publishedAt as string).getTime(), Date.now())).toISOString()}#${postRkey}`,
       entityType: 'timeline-item',
       authorDid,
       rkey: postRkey,
diff --git a/infra/indexer/src/index.ts b/infra/indexer/src/index.ts
index f7f9c84..939037c 100644
--- a/infra/indexer/src/index.ts
+++ b/infra/indexer/src/index.ts
@@ -357,7 +357,7 @@ async function fanInExistingPosts(readerDid: string, authorDid: string, publicat
     const postRkey = (post.SK as string).slice('p#'.length)
     const item: Record<string, unknown> = {
       PK: `u#${readerDid}#timeline`,
-      SK: `${new Date(Math.min(new Date(post.publishedAt as string).getTime(), Date.now())).toISOString()}#${postRkey}`,
+      SK: `${(post.GSI1SK as string | undefined)?.split('#')[0] ?? new Date(Math.min(new Date(post.publishedAt as string).getTime(), Date.now())).toISOString()}#${postRkey}`,
       entityType: 'timeline-item',
       authorDid,
       rkey: postRkey,