I'm using an LG Optimus Quantum and when I load up Gmaps or the default Maps app, I get nothing displayed on the screen...just a blinking indicator of my location but no actual map behind it.
Check to see that you have a data connection. Both apps require a data connection to download the maps. If your connection isn't strong enough then you might not be able to download all the information for the apps to draw the map.
I could confirm that this is known issue and we are working on fix.
Try to update to 1.19 and if you still have the same issue then as workaround when you see no map press the following:
1. "win" to deactivate app
2. "back" to activate it back and force map loading on required zoom level.