diff --git a/feature/favorites/src/commonMain/kotlin/io/github/droidkaigi/confsched/favorites/section/FavoriteSheet.kt b/feature/favorites/src/commonMain/kotlin/io/github/droidkaigi/confsched/favorites/section/FavoriteSheet.kt
index a3784142a..c9bf7c2dd 100644
--- a/feature/favorites/src/commonMain/kotlin/io/github/droidkaigi/confsched/favorites/section/FavoriteSheet.kt
+++ b/feature/favorites/src/commonMain/kotlin/io/github/droidkaigi/confsched/favorites/section/FavoriteSheet.kt
@@ -71,7 +71,7 @@ sealed interface FavoritesSheetUiState {
             val startTimeString: String,
             val endTimeString: String,
         ) {
-            val key: String get() = "${day?.name}$startTimeString-$endTimeString"
+            val key: String get() = "${day?.ordinal}-$startTimeString-$endTimeString"
         }
     }