diff --git a/packages/backend/src/server/api/endpoints/notes/local-timeline.ts b/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
index 9d5688f96f..3b6c93fdf9 100644
--- a/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
@@ -163,6 +163,18 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 					query.andWhere('note.fileIds != \'{}\'');
 				}
 
+				if (!ps.withReplies) {
+					query.andWhere(new Brackets(qb => {
+						qb
+							.where('note.replyId IS NULL') // 返信ではない
+							.orWhere(new Brackets(qb => {
+								qb // 返信だけど投稿者自身への返信
+									.where('note.replyId IS NOT NULL')
+									.andWhere('note.replyUserId = note.userId');
+							}));
+					}));
+				}
+
 				const timeline = await query.limit(ps.limit).getMany();
 
 				process.nextTick(() => {
diff --git a/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts b/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts
index ea3655f6bb..f937b5f9e1 100644
--- a/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts
+++ b/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts
@@ -60,7 +60,7 @@ export default function(props: {
 		switch (token.type) {
 			case 'text': {
 				let text = token.props.text.replace(/(\r\n|\n|\r)/g, '\n');
-				if (!disableNyaize && props.author.isCat) {
+				if (!disableNyaize && props.author?.isCat) {
 					text = nyaize(text);
 				}