diff --git a/lib/cast.js b/lib/cast.js
index 3dfd651acd2..94bdb1d2b9e 100644
--- a/lib/cast.js
+++ b/lib/cast.js
@@ -28,8 +28,10 @@ module.exports = function cast(schema, obj, options, context) {
   }
 
   // bson 1.x has the unfortunate tendency to remove filters that have a top-level
-  // `_bsontype` property. Should remove this when we upgrade to bson 4.x. See gh-8222
-  if (obj.hasOwnProperty('_bsontype')) {
+  // `_bsontype` property. But we should still allow ObjectIds because
+  // `Collection#find()` has a special case to support `find(objectid)`.
+  // Should remove this when we upgrade to bson 4.x. See gh-8222, gh-8268
+  if (obj.hasOwnProperty('_bsontype') && obj._bsontype !== 'ObjectID') {
     delete obj._bsontype;
   }