1 files changed, 8 insertions, 5 deletions
diff --git a/models/cards.js b/models/cards.js
index 633a3888..fd491372 100644
--- a/models/cards.js
+++ b/models/cards.js
@@ -1195,11 +1195,14 @@ Cards.mutations({
   },
 
   assignAssignee(assigneeId) {
-    return {
-      $addToSet: {
-        assignees: assigneeId,
-      },
-    };
+    // If there is not any assignee, allow one assignee, not more.
+    if (this.getAssignees().length === 0) {
+      return {
+        $addToSet: {
+          assignees: assigneeId,
+        },
+      };
+    }
   },
 
   unassignMember(memberId) {