diff --git a/src/savegame_json.cpp b/src/savegame_json.cpp
index 8b120a490e5db..72cddd63c5cbd 100644
--- a/src/savegame_json.cpp
+++ b/src/savegame_json.cpp
@@ -4581,15 +4581,15 @@ void ter_furn_migrations::load( const JsonObject &jo )
     furn_str_id to_furn = furn_str_id::NULL_ID();
     if( is_ter_migration ) {
         ter_str_id from_ter;
-        mandatory( jo, true, "from_ter", from_ter );
-        mandatory( jo, true, "to_ter", to_ter );
-        optional( jo, true, "to_furn", to_furn );
+        mandatory( jo, false, "from_ter", from_ter );
+        mandatory( jo, false, "to_ter", to_ter );
+        optional( jo, false, "to_furn", to_furn );
         ter_migrations.insert( std::make_pair( from_ter, std::make_pair( to_ter, to_furn ) ) );
     } else {
         furn_str_id from_furn;
-        mandatory( jo, true, "from_furn", from_furn );
-        optional( jo, true, "to_ter", to_ter );
-        mandatory( jo, true, "to_furn", to_furn );
+        mandatory( jo, false, "from_furn", from_furn );
+        optional( jo, false, "to_ter", to_ter );
+        mandatory( jo, false, "to_furn", to_furn );
         furn_migrations.insert( std::make_pair( from_furn, std::make_pair( to_ter, to_furn ) ) );
     }
 }