diff --git a/lib/schema/boolean.js b/lib/schema/boolean.js
index 37b4d51e0a0..c2640841cf1 100644
--- a/lib/schema/boolean.js
+++ b/lib/schema/boolean.js
@@ -230,7 +230,10 @@ SchemaBoolean.prototype.castForQuery = function($conditional, val) {
  */
 
 SchemaBoolean.prototype._castNullish = function _castNullish(v) {
-  if (typeof v === 'undefined' && this.$$context != null && this.$$context._mongooseOptions.omitUndefined) {
+  if (typeof v === 'undefined' &&
+      this.$$context != null &&
+      this.$$context._mongooseOptions != null &&
+      this.$$context._mongooseOptions.omitUndefined) {
     return v;
   }
   const castBoolean = typeof this.constructor.cast === 'function' ?
diff --git a/lib/schematype.js b/lib/schematype.js
index 82dd98ef568..38a3d3dbe8c 100644
--- a/lib/schematype.js
+++ b/lib/schematype.js
@@ -1461,12 +1461,19 @@ SchemaType.prototype.$conditionalHandlers = {
 SchemaType.prototype.castForQueryWrapper = function(params) {
   this.$$context = params.context;
   if ('$conditional' in params) {
-    return this.castForQuery(params.$conditional, params.val);
+    const ret = this.castForQuery(params.$conditional, params.val);
+    this.$$context = null;
+    return ret;
   }
   if (params.$skipQueryCastForUpdate || params.$applySetters) {
-    return this._castForQuery(params.val);
+    const ret = this._castForQuery(params.val);
+    this.$$context = null;
+    return ret;
   }
-  return this.castForQuery(params.val);
+
+  const ret = this.castForQuery(params.val);
+  this.$$context = null;
+  return ret;
 };
 
 /**