diff --git a/lib/document.js b/lib/document.js
index b91627899e1..78621707a2c 100644
--- a/lib/document.js
+++ b/lib/document.js
@@ -726,7 +726,6 @@ Document.prototype.$init = function() {
 
 Document.prototype.$__init = function(doc, opts) {
   this.$isNew = false;
-  this.$init = true;
   opts = opts || {};
 
   // handle docs with populated paths
@@ -988,8 +987,11 @@ Document.prototype.$session = function $session(session) {
       'called `endSession()` on the session you are passing to `$session()`.');
   }
 
-  this.$__.session = session;
+  if (session == null && this.$__.session == null) {
+    return;
+  }
 
+  this.$__.session = session;
 
   if (!this.$isSubdocument) {
     const subdocs = this.$getAllSubdocs();
diff --git a/lib/internal.js b/lib/internal.js
index 7e534dc994f..beab97fc5aa 100644
--- a/lib/internal.js
+++ b/lib/internal.js
@@ -11,12 +11,10 @@ module.exports = exports = InternalCache;
 
 function InternalCache() {
   this.activePaths = new ActiveRoster;
-
-  // embedded docs
-  this.ownerDocument = undefined;
-  this.fullPath = undefined;
+  this.strictMode = undefined;
 }
 
+InternalCache.prototype.fullPath = undefined;
 InternalCache.prototype.strictMode = undefined;
 InternalCache.prototype.selected = undefined;
 InternalCache.prototype.shardval = undefined;
@@ -28,6 +26,7 @@ InternalCache.prototype.inserting = undefined;
 InternalCache.prototype.saving = undefined;
 InternalCache.prototype.version = undefined;
 InternalCache.prototype._id = undefined;
+InternalCache.prototype.ownerDocument = undefined;
 InternalCache.prototype.populate = undefined; // what we want to populate in this doc
 InternalCache.prototype.populated = undefined;// the _ids that have been populated
 InternalCache.prototype.wasPopulated = false; // if this doc was the result of a population
diff --git a/lib/queryhelpers.js b/lib/queryhelpers.js
index 7fdebdb6303..8b495aca8eb 100644
--- a/lib/queryhelpers.js
+++ b/lib/queryhelpers.js
@@ -111,16 +111,16 @@ exports.createModel = function createModel(model, doc, fields, userProvidedField
       return new discriminator(undefined, _fields, true);
     }
   }
-  if (typeof options === 'undefined') {
-    options = {};
-    options.defaults = true;
-  }
-  return new model(undefined, fields, {
+
+  const _opts = {
     skipId: true,
     isNew: false,
-    willInit: true,
-    defaults: options.defaults
-  });
+    willInit: true
+  };
+  if (options != null && 'defaults' in options) {
+    _opts.defaults = options.defaults;
+  }
+  return new model(undefined, fields, _opts);
 };
 
 /*!
diff --git a/lib/types/subdocument.js b/lib/types/subdocument.js
index de686896c72..d22ed4451fd 100644
--- a/lib/types/subdocument.js
+++ b/lib/types/subdocument.js
@@ -19,7 +19,10 @@ module.exports = Subdocument;
 function Subdocument(value, fields, parent, skipId, options) {
   if (parent != null) {
     // If setting a nested path, should copy isNew from parent re: gh-7048
-    const parentOptions = { isNew: parent.isNew, defaults: 'defaults' in parent.$__ ? parent.$__.defaults : true };
+    const parentOptions = { isNew: parent.isNew };
+    if ('defaults' in parent.$__) {
+      parentOptions.defaults = parent.$__.defaults;
+    }
     options = Object.assign({}, parentOptions, options);
   }
   if (options != null && options.path != null) {