Both is not a drama, but just at the beginning lets you look at it slightly 'fooled. I built this example charger, my phone lying down, the LED is red and then green and was then been made. No more reaction, no matter what I'm doing. The explanation is simple, the phone was fully charged, so there was nothing to load, nothing lights up.
When the phone has been used then a couple of hours and was then placed on the charger, the green LED is lit up and the phone was charged.
By slipping the Nexus I have no problems. Charger is at the desk, charger is flat and slightly rubberized surface. Sure, it would be on a bedside table, the touching now and then, then the phone might move. Then a bright LED would interfere.
I have now ordered two more chargers.