Sorry, I should have been less cryptic in my earlier response. 
Devices don’t connect to gateways, but just transmit and hope that one or more gateways receive their radio transmission. They don’t know if any gateway received it (unless using confirmed uplinks, which you should not do every 10 seconds and which I assume you would have mentioned).
So, it’s not likely that powering off is related to the transmissions being received or not.