diff --git a/edb/server/protocol/auth_ext/webauthn.py b/edb/server/protocol/auth_ext/webauthn.py
index a50bd69a675..4d0f873b4f9 100644
--- a/edb/server/protocol/auth_ext/webauthn.py
+++ b/edb/server/protocol/auth_ext/webauthn.py
@@ -390,7 +390,7 @@ async def _get_authentication_challenge(
     created_at,
     modified_at,
     challenge,
-    factors: {
+    factors := (distinct (.factors union .factor)) {
         id,
         created_at,
         modified_at,