I have an SPA with roughly the following structure:
neon-animated-pages
neon-animatable web component
If the google-map page is not selected while loading, it fails to render correctly.

By sheer luck I resized the window discovering that it fixed the issue.

Possible Workarounds
(active is a property that is changed to true when the page is selected).
<template is="dom-if" if="[[active]]">
<google-map latitude="{{_lat}}" longitude="{{_lng}}" fit-to-markers single-info-window>
...
or
_activeChanged: function(active) {
this.$$('google-map').resize();
}