diff --git a/src/wp-admin/js/customize-controls.js b/src/wp-admin/js/customize-controls.js
index 56c061f04a..b43c1df109 100644
--- a/src/wp-admin/js/customize-controls.js
+++ b/src/wp-admin/js/customize-controls.js
@@ -4299,6 +4299,7 @@
 			var previewer = this, synced = {}, constructs;
 
 			synced.settings = api.get();
+			synced['settings-modified-while-loading'] = previewer.settingsModifiedWhileLoading;
 			if ( 'resolved' !== previewer.deferred.active.state() || previewer.loading ) {
 				synced.scroll = previewer.scroll;
 			}
@@ -4421,7 +4422,7 @@
 		 * Refresh the preview seamlessly.
 		 */
 		refresh: function() {
-			var previewer = this;
+			var previewer = this, onSettingChange;
 
 			// Display loading indicator
 			previewer.send( 'loading-initiated' );
@@ -4435,6 +4436,15 @@
 				container:  previewer.container
 			});
 
+			previewer.settingsModifiedWhileLoading = {};
+			onSettingChange = function( setting ) {
+				previewer.settingsModifiedWhileLoading[ setting.id ] = true;
+			};
+			api.bind( 'change', onSettingChange );
+			previewer.loading.always( function() {
+				api.unbind( 'change', onSettingChange );
+			} );
+
 			previewer.loading.done( function( readyData ) {
 				var loadingFrame = this, previousPreview, onceSynced;
 
diff --git a/src/wp-includes/js/customize-preview.js b/src/wp-includes/js/customize-preview.js
index 484ccf4acc..be24e414bf 100644
--- a/src/wp-includes/js/customize-preview.js
+++ b/src/wp-includes/js/customize-preview.js
@@ -654,6 +654,25 @@
 		});
 
 		api.preview.bind( 'sync', function( events ) {
+
+			/*
+			 * Delete any settings that already exist locally which haven't been
+			 * modified in the controls while the preview was loading. This prevents
+			 * situations where the JS value being synced from the pane may differ
+			 * from the PHP-sanitized JS value in the preview which causes the
+			 * non-sanitized JS value to clobber the PHP-sanitized value. This
+			 * is particularly important for selective refresh partials that
+			 * have a fallback refresh behavior since infinite refreshing would
+			 * result.
+			 */
+			if ( events.settings && events['settings-modified-while-loading'] ) {
+				_.each( _.keys( events.settings ), function( syncedSettingId ) {
+					if ( api.has( syncedSettingId ) && ! events['settings-modified-while-loading'][ syncedSettingId ] ) {
+						delete events.settings[ syncedSettingId ];
+					}
+				} );
+			}
+
 			$.each( events, function( event, args ) {
 				api.preview.trigger( event, args );
 			});