I have 3 Decos on three different floors, main deco is on the middle floor. Now once a week,(maybe more or less) the deco on the first floor seems to disconnect and just loose connectivity. 

No rhyme or reason and it will only have 2-3 devices on it, no doors even between these decos. Having said that, even if I take this disconnected Deco and place it right next to the main it will not reconnect to the main one. Rebooting the modem, main deco, satellite deco - doesn't resolve the issue. The only way to quickly fix it, is to factory reset the satellite deco. 

ISP or other devices are not experiencing drops or connectivity issues.


Edit: It's back downstairs and it finally reconnected hours later, while it was downstairs, (without factory resetting it)....