diff --git a/lib/mixins/property-accessors.js b/lib/mixins/property-accessors.js
index bd2cb77b8a..3a9ccaf6b5 100644
--- a/lib/mixins/property-accessors.js
+++ b/lib/mixins/property-accessors.js
@@ -291,6 +291,7 @@ export const PropertyAccessors = dedupingMixin(superClass => {
      */
     _definePropertyAccessor(property, readOnly) {
       if (legacyNoBatch) {
+        // Ensure properties are not flushed when adding instance effects
         const ready = this.__dataReady;
         this.__dataReady = false;
         saveAccessorValue(this, property);
diff --git a/lib/mixins/property-effects.js b/lib/mixins/property-effects.js
index 83bca57070..5580cd9e24 100644
--- a/lib/mixins/property-effects.js
+++ b/lib/mixins/property-effects.js
@@ -1570,7 +1570,8 @@ export const PropertyEffects = dedupingMixin(superClass => {
         this._flushClients();
         // Capture element data and flush properties one-by one to defeat
         // Polymer 2.x's batched _propertiesChanged scheme; this approximates
-        // 1.x's applyConfig
+        // 1.x's applyConfig. Data is reset to mimic 1.x behavior of
+        // properties incrementally being initialized
         const changedProps = this.__data;
         const notify = this.__dataToNotify;
         this.__data = {};
@@ -1732,7 +1733,9 @@ export const PropertyEffects = dedupingMixin(superClass => {
       // Compute properties
       if (legacyNoBatch) {
         // When not batching, computed effects may re-enter, so capture
-        // notifying properties early
+        // notifying properties early. Use simple runEffects rather than
+        // runComputedEffects since computed effects will run immediately
+        // rather than being batched.
         notifyProps = this.__dataToNotify;
         this.__dataToNotify = null;
         runEffects(this, this[TYPES.COMPUTE], changedProps, oldProps, hasPaths);