Hi Guys,
just to contribute on the problem:
Malaysian Version of Galaxy S7 Edge DUO (SM-G935FD)
Firmware G935FXXU1APB6
FitbitHR with allday sync enabled
RT-AC68U router with Merlin, running Wifi on 2.4
Keeping Bluetooth always On due to Fitbit
No DD on my device
Having same issues with Wifi...