diff --git a/plume-common/src/utils.rs b/plume-common/src/utils.rs
index d60db844..7759a25e 100644
--- a/plume-common/src/utils.rs
+++ b/plume-common/src/utils.rs
@@ -442,6 +442,7 @@ mod tests {
             ("not_a#hashtag", vec![]),
             ("#نرم‌افزار_آزاد", vec!["نرم‌افزار_آزاد"]),
             ("[#hash in link](https://example.org/)", vec![]),
+            ("#zwsp\u{200b}inhash", vec!["zwsp"]),
         ];
 
         for (md, mentions) in tests {