diff --git a/files/routes/posts.py b/files/routes/posts.py
index 7704e0855..a15d92ece 100644
--- a/files/routes/posts.py
+++ b/files/routes/posts.py
@@ -181,7 +181,7 @@ def post_id(pid, anything=None, v=None):
 
 		post.preloaded_comments = [x for x in comments if not (x.author and x.author.shadowbanned) or (v and v.id == x.author_id)]
 
-	if session.get("read_comments"): read = list(session.get("read_comments"))
+	if session.get("read_comments"): read = list(set(session.get("read_comments")))
 	else: read = None
 	read_comments = [x.id for x in post.preloaded_comments]
 	if read: session["read_comments"] += read_comments