I have amp-iframe with google places on my website, the issue is that sometimes it renders and sometimes it doesn't.
For instance, in this URL it renders https://www.didomenicapalermo.com.ar/venta/casas/modernas-en-barrio-el-cazador-escobar/amp
<amp-iframe width="600" height="400" layout="responsive" sandbox="allow-scripts allow-same-origin allow-popups allow-popups-to-escape-sandbox allow-presentation" frameborder="0" src="https://www.google.com/maps/embed/v1/place?key=AIzaSyD6dkHc8fW_mUsoWRH7XZoje20cAfLqpjw&q= -34.30814559434459,-58.7645224110413&zoom=15"></amp-iframe>
But in thoose URL's it doesn't https://www.didomenicapalermo.com.ar/venta/terrenos/y-lotes-en-esquina-comercial-de-escobar-zona-norte/amp
<amp-iframe width="600" height="400" layout="responsive" sandbox="allow-scripts allow-same-origin allow-popups allow-popups-to-escape-sandbox allow-presentation" frameborder="0" src="https://www.google.com/maps/embed/v1/place?key=AIzaSyD6dkHc8fW_mUsoWRH7XZoje20cAfLqpjw&q=-34.340968537270385,-58.78817459781499&zoom=15"></amp-iframe>
https://www.didomenicapalermo.com.ar/venta/terrenos/con-todos-los-servicios-escobar/amp
<amp-iframe width="600" height="400" layout="responsive" sandbox="allow-scripts allow-same-origin allow-popups allow-popups-to-escape-sandbox allow-presentation" frameborder="0" src="https://www.google.com/maps/embed/v1/place?key=AIzaSyD6dkHc8fW_mUsoWRH7XZoje20cAfLqpjw&q=-34.33815254252059,-58.797808417633064&zoom=15"></amp-iframe>
https://www.didomenicapalermo.com.ar/venta/terrenos/con-agua-corriente-cloacas-escobar/amp
<amp-iframe width="600" height="400" layout="responsive" sandbox="allow-scripts allow-same-origin allow-popups allow-popups-to-escape-sandbox allow-presentation" frameborder="0" src="https://www.google.com/maps/embed/v1/place?key=AIzaSyD6dkHc8fW_mUsoWRH7XZoje20cAfLqpjw&q=-34.343364984291966,-58.78496684381105&zoom=15"></amp-iframe>
Double checked the code, and it seems to be ok for me, but still fails in some URL's.
PS: No 600px error!
Your issue is that amp-iframe is missing from the pages where Google Map is not rendering.
Add amp-iframe
<script async custom-element="amp-iframe" src="https://cdn.ampproject.org/v0/amp-iframe-0.1.js">
</script>
Also, your AMP pages are invalid. You can validate AMP pages here